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Science (Core Physics - Generating Electricity (Energy and the Environment…

- - - - Chloroplasts are organelles found in plant cells and eukaryotic algae that conduct photosynthesis. Chloroplasts absorb sunlight and use it in conjunction with water and carbon dioxide gas to produce food for the plant.
        
        Photosynthesis
        
        carbon dioxide + water -sunlight> glucose + oxygen
        
        6CO2 + 6H2O —> C6H12O6 + 6O2
        
        Photosynthesis is a chemical reaction that takes place inside a plant, producing food for the plant to survive. Carbon dioxide, water and light are all needed for photosynthesis to take place. Photosynthesis happens in the leaves of a plant.
        
        What is Photosynthesis?
        
        what is a chloroplast?
    - - A cell wall is a structural layer surrounding some types of cells, just outside the cell membrane. It can be tough, flexible, and sometimes rigid. It provides the cell with both structural support and protection, and also acts as a filtering mechanism.
        
        What is a Cell Wall?
    - - Contains cell sap, a week solution of sugar and salts
        
        What is Permanent vacuole?
  - - - Holds the cell together and controls what goes in and out
        
        What is a Cell membrane?
    - - Gel-like substance where most of the chemical reactions happen it contains enzymes
        
        What is a Cytoplasm?
    - - These are where most of the reactions for aerobic respiration take place. Respiration transfers energy
        
        What is a Mitochondria?
    - - These are where proteins are made in the cell
        
        What is a Ribosomes?
    - - Contains genetic material that controls the activities
        
        What is a Nucleus?
- - - - Respiration and gas exchange
        
        Gas exchange is the delivery of oxygen from the lungs to the bloodstream, and the elimination of carbon dioxide from the bloodstream to the lungs and out of the body. It takes place in the alveoli. The walls of the alveoli are surrounded by a network of blood capillaries.
        
        What is Respiration and gas exchange?
    - - It's separated from the lower part of the body by the diaphagm.
        
        The lungs are like big pink sponges and are protected by the ribcage. They're surrounded by the plural membranes
        
        The air that you breath in the goes through the trachea. This splits into two tubes called bronchi, one going to each lung
        
        The bronchi splits into progressively smaller tubes called bronchioles
        
        The bronchioles finally end at small bags called alveoli where the gas exchange takes place
  - - - Left Atrium
      - Right Ventricle
        
        Right Atrium
    - - The largest artery is the aorta, the main high-pressure pipeline connected to the heart's left ventricle. The aorta branches into a network of smaller arteries that extend throughout the body. The arteries' smaller branches are called arterioles and capillaries.
- - - - Count Rate: The number of counts per second detected by the Geiger counter. This is proportional to the activity of the source as long as the distance between the tube and the source stays the same.
      - Half-life: The half life of a radioactive material is the time (average) it takes for the number of nuclei of the isotope in a sample to halve.
      - Activity: The activity of a radioactive source is the number of unstable atoms in the source that decay per second.
    - - Nuclear Equations show radioactive decay:
        Mass and atomic numbers have to balance:
        1) Nuclear equations are a way of showing radioactive decay by using element symbols.
        2) They're written in the form: atom before decay = atom after decay + radiation emitted.
        3) There is one rule to remember; the total mass and atomic numbers must be equal on both sides.
      - Gamma Rays don't change the charge or mass of the nucleus:
        1) Gamma rays are a way of getting rid of excess energy from a nucleus.
        2) This means that there is no change to the atomic mass or atomic number of the atom.
      - Beta Decay increases the charge of the nucleus:
        1) When beta decay occurs, a neutron in the nucleus turns into a proton and releases a fast-moving electron (the beta particle).
        2) The number of protons in the nucleus has increased by 1. This increases the positive charge of the nucleus (the atomic number).
        3) Because the nucleus has lost a neutron and gained a proton during beta decay, the mass of the nucleus doesn't change (protons and neutrons have the same mass).
      - Alpha Decay decreases the charge and mass of the nucleus:
        1) remember, alpha particles are made up of two protons and two neutrons. So when an atom emits an alpha particle, its atomic number reduces by 2 and its mass number reduces by 4.
        2) A proton is positively charged and a neutron is neutral, so the charge of the nucleus decreases.
        3) In nuclear equations, an alpha particle can be written as a helium nucleus.
    - - 1) The nuclear model that resulted from the alpha particle scattering experiment was a positively charged nucleus surrounded by a cloud of negative electrons.
        2) Niels Bohr said that electrons orbiting the nucleus do so at certain distances called energy levels. His theoretical calculations agreed with experiment data.
        3) Evidence from further experiments changed the model to have a nucleus made up of a group of particles (protons) which all had the same positive charge that added up to the overall charge of the nucleus.
        4) About 20 years after the idea of a nucleus was accepted, in 1932, James Chadwick proved the existence of the neutron which explained the imbalance between the atomic and mass numbers.
      - The nucleus is tiny but makes up most of the mass of the atom
        
        It contains protons (which are positively charged - they have a +1 relative charge) and neutrons (which are neutral, with a relative charge of 0) - which gives it an overall positive charge.
        
        The rest of the atom is mostly empty space. Negative electrons (relative charge -1) whizz round the outside of the nucleus really fast
        
        The number of protons = the number of electrons, as protons and electrons have an equal but opposite charge and atoms have no overall charge
    - - Count Rate:
        The count rate after n half-lives = the initial count rate divided by 2n.
      - You can measure half-life using a graph:
        1) If you plot a graph of activity against time.
        2) The half-life is found from the graph by finding the time interval on the bottom axis corresponding to a halving of the activity on the vertical axis.
      - Radioactivity is a totally random process:
        1) Radioactive substances give out radiation from the nuclei of their atoms - no matter what
        2) This radiation can be measured with a Geiger-Muller tube and counter, which records the count-rate - the number of radiation counts reaching it per second.
        3) Radioactive decay is entirely random. So you can't predict exactly which nucleus in a sample will decay next, or when any one of them will decay.
        4) But you can find out the time it takes for the amount of radiation emitted by a source to halve, this is known as the half life. It can be used to make predictions about radioactive sources, even though their decays are random.
        5) Half-life can be used to find the rate at which a source decays - its activity. Activity is measured in Becquerels. Bq (where 1 Bq is 1 decay per second).
      - The Radioactivity of a source decreases over time:
        1) Each time a radioactive nucleus decays to become a stable nucleus, the activity as a whole will decrease. (older sources emit less radiation).
        2) For some isotopes it takes just a few hours before nearly all the unstable nuclei have decayed, whilst others last for millions of years.
        3) The problem with trying to measure this is that the activity never reaches zero, which is why we have to use the idea of half-life to measure how quickly the activity drops off.
        
        The half-life is the time taken for the number of radioactive nuclei in an isotope to halve *
        4) Half-life can also be described as the time taken for the activity (and so count-rate) to fall to half of its initial value.
    - - Gamma Rays:
        
        Gamma rays are waves of electromagnetic radiation released by the nucleus.
        
        They penetrate far into materials without being stopped and will travel a long distance in air.
        
        This means they are weakly ionising because they tend to pass through rather than collide with atoms. Eventually they hit something and do damage.
        
        They can be absorbed by thick sheets of lead or metres of concrete.
      - Beta Particles:
        
        A beta particle (B) is simply a fast-moving electron released by the nucleus. Beta particles have virtually no mass and a charge of -1.
        
        They are moderately ionising. They penetrate moderately far into materials before colliding and have a range in air of a few metres. They are absorbed by a sheet of aluminium (around 5mm).
        
        For every beta particle emitted, a neutron in the nucleus has turned into a proton.
      - Alpha Particles:
        
        Alpha radiation is when an alpha particle (a) is emitted from the nucleus. An a-particle is two protons and two neutrons.
        
        They don't penetrate very far into materials and are stopped quickly - they can only travel a few cm in air and are absorbed by a sheet of paper.
        
        Because of their size they are strongly ionising.
      - Isotopes are different forms of the same element
        
        All atoms of each element have a set number of protons.
        
        The number of protons in an atom is its atomic number
        
        The mass number of an atom is the number of protons + the number of neutrons
        
        Isotopes of an element are atoms with the same number of protons (same atomic number) but a different number of neutrons (different mass number)
        
        All elements have different isotopes, but there are usually only one or two stable ones
      - Unstable Isotopes:
        
        The unstable isotopes tend to decay into other elements and give out radiation as they try to become more stable (they try to balance the number of protons and neutrons in their nucleus or get rid of any excess energy). This process is called Radioactive Decay.
        
        Radioactive substances spit out one or more types of ionising radiation from their nucleus - alpha, beta or gamma radiation.
        
        They can also release neutrons when they decay to rebalance the number of protons and neutrons.
        
        Ionising radiation is radiation that knocks electrons off atoms creating positive ions.
  - - - Thermal insulators
        
        You can also investigate the effectiveness of the thickness of a material
        
        The lower the temp difference after 5 mins, the better an insulator it is
        
        Make sure the starting mass and temperature of the water are constant
        
        Repeat the experiment, but wrap the container in an insulator like foil or newspaper once sealed
        
        Measure the temp after 5 mins, then pour away the water and allow the container to cool to room temperature
        
        Seal the container and leave it for 5 mins - use a stopwatch
        
        Use a thermometer to measure the initial temperature of the water
        
        Boil water in a kettle, then pour some into a sealable container, and measure mass of water in the container
      - Density of materials
        
        Density of a liquid
        
        Finally, take an average if the calculated densities
        
        For each measurement, find the density of the liquid
        
        Pour another 10ml, and repeat the process until the cylinder is full while recording the total vol and mass each time
        
        Pour 10ml of liquid into the measuring cylinder and record the liquids mass
        
        Place a measuring cylinder on a balance and set it to 0
        
        Find the density of a solid object
        
        Then place the vol and mass into the formula p = m/v
        
        For an irregular solid, submerge it in a eureka can filled with water, then see how much water is displaced, as this is equivalent to vol of the object
        
        If it's regular, measure its length, width and height then calculate density using p = m/v
        
        Use a balance to measure its mass
      - Resistance
        
        Adding resistors in parallel
        
        Repeat until all resistors are added, then plot a graph of number of resistors against total resistance - should be asymptotic, starts high then decreases at a decreasing speed, tending towards 0 but never reaching it
        
        Measure the total current through the circuit and again calculate the overall resistance of the circuit
        
        Add another resistor, but in parallel
        
        Measure the total current of the circuit and calculate the resistance of the circuit using V = IR
        
        Using the same equipment, build the initial same circuit
        
        Adding resistors in series
        
        Need at least four identical resistors
        
        Build a circuit with the resistor, a battery and an ammeter - make sure the pd of the battery is recorded
        
        Measure the current through the ammeter, then calculate the resistance of the circuit using V = IR
        
        Do this until all of the resistors have been added, then plot a graph of number of resistors against total resistance - should be a straight line
        
        Add another resistor in series, and then calculate the resistance again
      - Factors affecting resistance
        
        Resistance depends on factors such as whether it's parallel or series or the length of wire
        
        Length of wire
        
        Graph should be a straight line through the origin,a s resistance is directly proportional to to length
        
        Calculate the resistance using V = IR, then plot a graph of length against resistance
        
        Repeat this with a number of different lengths
        
        Open the switch, and move the second clip further back, then record the new length, pd or current
        
        Close the switch and then record the current in the wire and the pd across it
        
        Attach a second crocodile clip to the wire and write down the length of wire between the 2 clips
        
        Attach a crocodile clip to the wire level with 0 on the ruler
      - I-V characteristics
        
        Diode
        
        Graph is a steep line on one side of the graph
        
        Current will only flow through a diode in one direction, so the diode has a very high resistance in one direction
        
        Filament lamp
        
        The graph is a curve steep at first but becoming more shallow
        
        As the current increases, the temp of the filament increases, so the resistance increases, so then the current decreases
        
        Ohmic conductor eg. fixed resistor
        
        Graph is a straight line
        
        Current through an ohmic conductor, at constant temperature, is directly proportional to the potential difference
        
        Plot a graph of current against voltage for the component
        
        Swap the wires connected to the cell so they become reversed so the direction of current is reversed
        
        Repeat each reading twice to get an average pd
        
        Take several pairs of readings from the ammeter and voltmeter to see how the pd varies as the current changes
        
        By varying the variable resistor this alters the current flowing through the circuit and the pd across the component
        
        Non-linear components have a curve on their graph eg. filament lamp or a diode
        
        Linear components have a straight line on their graph eg. ohmic conductor
        
        Graphs which show how current flowing through a component changes as the pd is increased
      - Specific heat capacity
        
        Measure the mass of the block, then insulate it to reduce the energy transferred from the block to the surroundings eg. with newspaper
        
        After 10 readings, turn off the power and calculate the specific heat capacity using the reading from the joulemeter, or by finding the power using P = VI, then finding the energy transferred using E = Pt
        
        As the block heats up, take readings of the temp and current, or of the joulemeter every minute for 10 mins - the current shouldn't change
        
        This energy is transferred to the materials thermal energy store via heating, causing the materials temp to increase
        
        When the power is turned on, the current in the circuit does work on the heater, transferring energy electrically from the power supply to the heaters thermal energy store
        
        Measure the initial temp of the block and set the pd of the power supply to 10V, then turn on the power supply and start a stopwatch
        
        Insert the thermometer and heater into the two holes in the block
    - - EM spectrum
        -transverse waves
        -they consist of vibrating electric and magnetic fields hence can travel though a vacuum
        speed:in a vacuum they travel at 3.00 x 10 m/s
        
        dangers of EM radiation
        heating and burns: can cause cells to heat up and infrared is reflected by your skin but some of it is absorbed leads to burns if its to hot
        skin cancer and eye conditions:ionizing radiation when absorbed can cause damage to the cell on the surface of your skin=cancer and damage cell in your eyes
        
        gamma rays
        sterilization: kills the microbes in the food that make the food go bad so it doesn't rot as quickly and medical equipment.
        detecting and treating cancer: injected into a patient and can track how much of the substance different parts of the body use.
        
        x-rays
        medical imaging: passes easily though flesh but not though denser material like bone/metal.
        airport security
        
        UV radiation
        when UV radiation hits them its absorbed and visible light is emitted
        security: identify forged bank notes
        fluorescent lamps
        disinfecting water:UV radiation transfers enough energy that it can kill cells
        
        infrared radiation
        thermal imagining
        security systems: e.g. if infrared radiation is detected from an intruder the alarm goes off
        cooking: wavelengths which allow them to be absorbed by water molecules in food
        
        EM radiation for communication
        how are radio waves produced?:alternating current in an electrical circuit
        how are radio waves received?:transmitted radio waves reach the receiver they are absorbed
        
        properties of EM waves
        if an atom absorbs energy some of its electrons move to a higher energy level.
        nuclear changes:
        all electromagnetic waves transfer energy from source to an absorber .e.g.a hot object transfers energy by emitting infrared radiation which is absorbed by the surroundings.
      - refraction:
        occurs because wave travels faster in some materials than others
      - equations
        acceleration=change in velocity/time taken
        force=mxa
        inertial mass(m)=f/a
        weight=massxgravitational field strength
        momentum(p)=massxvelocity
        ΔGPE = m× g ×Δh
        total energy input=useful energy output+wasted energy
        KE=1/2xmxv2(speed)
        efficiency=useful energy/total energy
        period(T)=1/frequency
        Wave speed(v)=frequencyxλ
      - waves:
        transverse waves :oscillate at right angles to the direction that they travel in
        
        longitudinal waves:the oscillations are parallel to the direction of travel
      - conservation of energy
        
        improving efficiency:
        you can reduce the amount of wasted energy by:
        -using lubricants
        -thermal insulation
        
        thermal conductivity
        cavity walls and double glazing: the air gap reduces the amount of energy transferred by conduction(air has a low thermal conductivity)
        loft insulation:fiber glass is an insulating material made of thin strands of glass that trap pockets of air-reduces conduction to the attic space
        hot water tank jacket:putting fiberglass wool around a hot water tank reduces energy transferred by conduction from the tanks thermal energy store to the surroundings
        
        lubrication:
        they are used to reduce friction between the objects surfaces when they move e.g oil
      - definitions
        vectors:magnitude and direction e.g.-velocity ,displacement, forces, momentum
        scalar:magnitude but no direction e.g.-distance, mass, energy and time
        centripetal force:this resultant force acts towards the center of a circle
        closed system:doesn't let energy in or out total change of energy is always 0
      - motion and forces
        
        vectors:magnitude and direction e.g.-velocity ,displacement, forces, momentum
        scalar:magnitude but no direction e.g.-distance, mass, energy and time
        
        newton's second law:
        -force+acceleration are directly proportional
        
        interia mass measures how difficult it is to change velocity of an object equation:m=f/a
        
        zero resultant force:
        -if its 0 on a moving object-it'll just carry on moving at the same velocity
        non-zero resultant force:
        -if there is non-0 resultant force on an object its velocity will change
        
        distance/time graph:gradient=speed
        flat line: stationary
        curve: acceleration/deceleration
        velocity/time graph:
        gradient: acceleration
        flat section: steady speed
        curve: changing acceleration
        
        stopping safety:
        a large deceleration causes a large force.
        -large force causes breaks to overheat and vehicles to skid.
    - - Key Terms
        
        Activity: The activity of a radioactive source is the number of unstable atoms in the source that decay per second.
        
        Count Rate: The number of counts per second detected by the Geiger counter. This is proportional to the activity of the source as long as the distance between the tube and the source stays the same.
        
        Half-life: The half life of a radioactive material is the time (average) it takes for the number of nuclei of the isotope in a sample to halve.
      - Nuclear Equations
        
        Nuclear Equations show radioactive decay:
        Mass and atomic numbers have to balance:
        1) Nuclear equations are a way of showing radioactive decay by using element symbols.
        2) They're written in the form: atom before decay = atom after decay + radiation emitted.
        3) There is one rule to remember; the total mass and atomic numbers must be equal on both sides.
        
        Gamma Rays don't change the charge or mass of the nucleus:
        1) Gamma rays are a way of getting rid of excess energy from a nucleus.
        2) This means that there is no change to the atomic mass or atomic number of the atom.
        
        Beta Decay increases the charge of the nucleus:
        1) When beta decay occurs, a neutron in the nucleus turns into a proton and releases a fast-moving electron (the beta particle).
        2) The number of protons in the nucleus has increased by 1. This increases the positive charge of the nucleus (the atomic number).
        3) Because the nucleus has lost a neutron and gained a proton during beta decay, the mass of the nucleus doesn't change (protons and neutrons have the same mass).
        
        Alpha Decay decreases the charge and mass of the nucleus:
        1) remember, alpha particles are made up of two protons and two neutrons. So when an atom emits an alpha particle, its atomic number reduces by 2 and its mass number reduces by 4.
        2) A proton is positively charged and a neutron is neutral, so the charge of the nucleus decreases.
        3) In nuclear equations, an alpha particle can be written as a helium nucleus.
      - The Atom
        
        1) The nuclear model that resulted from the alpha particle scattering experiment was a positively charged nucleus surrounded by a cloud of negative electrons.
        2) Niels Bohr said that electrons orbiting the nucleus do so at certain distances called energy levels. His theoretical calculations agreed with experiment data.
        3) Evidence from further experiments changed the model to have a nucleus made up of a group of particles (protons) which all had the same positive charge that added up to the overall charge of the nucleus.
        4) About 20 years after the idea of a nucleus was accepted, in 1932, James Chadwick proved the existence of the neutron which explained the imbalance between the atomic and mass numbers.
        
        The nucleus is tiny but makes up most of the mass of the atom
        
        It contains protons (which are positively charged - they have a +1 relative charge) and neutrons (which are neutral, with a relative charge of 0) - which gives it an overall positive charge.
        
        The rest of the atom is mostly empty space. Negative electrons (relative charge -1) whizz round the outside of the nucleus really fast
        
        The number of protons = the number of electrons, as protons and electrons have an equal but opposite charge and atoms have no overall charge
      - Half-Life
        
        Count Rate:
        The count rate after n half-lives = the initial count rate divided by 2n.
        
        You can measure half-life using a graph:
        1) If you plot a graph of activity against time.
        2) The half-life is found from the graph by finding the time interval on the bottom axis corresponding to a halving of the activity on the vertical axis.
        
        Radioactivity is a totally random process:
        1) Radioactive substances give out radiation from the nuclei of their atoms - no matter what
        2) This radiation can be measured with a Geiger-Muller tube and counter, which records the count-rate - the number of radiation counts reaching it per second.
        3) Radioactive decay is entirely random. So you can't predict exactly which nucleus in a sample will decay next, or when any one of them will decay.
        4) But you can find out the time it takes for the amount of radiation emitted by a source to halve, this is known as the half life. It can be used to make predictions about radioactive sources, even though their decays are random.
        5) Half-life can be used to find the rate at which a source decays - its activity. Activity is measured in Becquerels. Bq (where 1 Bq is 1 decay per second).
        
        The Radioactivity of a source decreases over time:
        1) Each time a radioactive nucleus decays to become a stable nucleus, the activity as a whole will decrease. (older sources emit less radiation).
        2) For some isotopes it takes just a few hours before nearly all the unstable nuclei have decayed, whilst others last for millions of years.
        3) The problem with trying to measure this is that the activity never reaches zero, which is why we have to use the idea of half-life to measure how quickly the activity drops off.
        
        The half-life is the time taken for the number of radioactive nuclei in an isotope to halve *
        4) Half-life can also be described as the time taken for the activity (and so count-rate) to fall to half of its initial value.
      - Isotopes and Nuclear Radiation
        
        Gamma Rays:
        
        Gamma rays are waves of electromagnetic radiation released by the nucleus.
        
        They penetrate far into materials without being stopped and will travel a long distance in air.
        
        This means they are weakly ionising because they tend to pass through rather than collide with atoms. Eventually they hit something and do damage.
        
        They can be absorbed by thick sheets of lead or metres of concrete.
        
        Beta Particles:
        
        A beta particle (B) is simply a fast-moving electron released by the nucleus. Beta particles have virtually no mass and a charge of -1.
        
        They are moderately ionising. They penetrate moderately far into materials before colliding and have a range in air of a few metres. They are absorbed by a sheet of aluminium (around 5mm).
        
        For every beta particle emitted, a neutron in the nucleus has turned into a proton.
        
        Alpha Particles:
        
        Alpha radiation is when an alpha particle (a) is emitted from the nucleus. An a-particle is two protons and two neutrons.
        
        They don't penetrate very far into materials and are stopped quickly - they can only travel a few cm in air and are absorbed by a sheet of paper.
        
        Because of their size they are strongly ionising.
        
        Isotopes are different forms of the same element
        
        All atoms of each element have a set number of protons.
        
        The number of protons in an atom is its atomic number
        
        The mass number of an atom is the number of protons + the number of neutrons
        
        Isotopes of an element are atoms with the same number of protons (same atomic number) but a different number of neutrons (different mass number)
        
        All elements have different isotopes, but there are usually only one or two stable ones
        
        Unstable Isotopes:
        
        The unstable isotopes tend to decay into other elements and give out radiation as they try to become more stable (they try to balance the number of protons and neutrons in their nucleus or get rid of any excess energy). This process is called Radioactive Decay.
        
        Radioactive substances spit out one or more types of ionising radiation from their nucleus - alpha, beta or gamma radiation.
        
        They can also release neutrons when they decay to rebalance the number of protons and neutrons.
        
        Ionising radiation is radiation that knocks electrons off atoms creating positive ions.
    - - science
        
        science main areas
        
        biology
        
        cell
        
        simple organism such as amoeba are made up of only one cell
        
        cell are the basic building unit of all living organism
        
        the majority
        
        diversity of living things
        
        biodiversity
        
        a measure of the total number of the different living plants and animals in an area
        
        biodiverse areas
        
        3 more items...
        
        species
        
        similar groups of animals or plants
        
        closely related species are called a genus ( plural:genera )
        
        the set of genus
        
        chemistrytext
        
        diversity of living things
        
        biodiversity
        
        biodiverse areas
        
        3 more items...
        
        a measure of the total number of the different living plants and animals in an area
        
        species
        
        similar groups of animals or plants
        
        closely related species are called a genus ( plural:genera )
        
        the set of genus
        
        chemical changes
        
        the effect of chemical change
        
        photosyntesis
        
        heating matter
        
        chemical reaction
        
        new substance that made because chemical reaction called product
        
        represent by word equation
        
        neutralization
        
        oxidation
        
        thermal decomposion
        
        combustion
        
        atom & molecules
        
        molecules
        
        atom that combine together
        
        atom
        
        can be split to nuclear energy that can be used to generated electricity for homes and factories
        
        maude up of 3 sub atomic particles
        
        3 more items...
        
        neural particle
        
        100 atom known
        
        represent as a circle
        
        cannot be seen even using a powerful microscope
        
        the smallest particle in the universe
        
        the particulate nature of matter
        
        a change in state
        
        condensing
        
        boiling
        
        freezing
        
        melting
        
        matter
        
        have kinetic energy
        
        not continous
        
        all around us
        
        made up of individual particles with spaces between the paricles
        
        the particulate theory of matter moving in a random manner
        
        made up of individual particles such as molecules or atoms which are arranged differently in solids,liquids, &gasses
        
        separation techniques
        
        compound
        
        using chemical reaction
        
        1 more item...
        
        mixture
        
        separate using physical properties of constituents of mixture
        
        7 more items...
        
        chemical composition of matter
        
        mixture
        
        heterogenous
        
        1 more item...
        
        homogenous
        
        1 more item...
        
        two or more substance that are not chemically combined
        
        most occur uncombined with other elemeents
        
        oxygen
        
        element is a substance which cannot be broken down into two or more simpler substances by chemical means
        
        all living and non living matter consist of basic units called elements
        
        some element uncombined on earth
        
        example; gold and silver
        
        the most abundant element is
        
        nitrogen
        
        all known elements are arranged in a chart called periodic table
        
        mixture
        
        1 more item...
        
        mixture
        
        compound is a substance made when twoo or more different elements chemically combine together
        
        elements in the periodic table can be classified into metals and non metals according to their different physical properties
        
        2 more items...
        
        each horizontal row in the periodic table is called a period
        
        each vertical column in the peoridic table is called a group
        
        every element is represented by a chemical symbol
        
        physics
        
        heat energy
        
        SI unit = kelvin
        
        measure using temperature
        
        heat transfer
        
        radiation
        
        1 more item...
        
        confection
        
        1 more item...
        
        conduction
        
        1 more item...
        
        make material expansion
        
        the use of expansion
        
        4 more items...
        
        sound energy
        
        frequenzy is measured byy heartz (Hz)
        
        speed
        
        speed of sound=distance travelled (m):time taken (s)
        
        much slower than the light
        
        330 metres per second
        
        reflect sound waves
        
        echo
        
        cannot travel through vacuum (empty space)
        
        made by vibrating objects
        
        energy and work done
        
        energy
        
        types of energy
        
        2 more items...
        
        immortal
        
        when work is done, energy is always tranfered
        
        energy is ability to do work
        
        formula
        
        work = force x distance
        
        when a force moves an object through a distance
        
        aplication of forces
        
        force
        
        pressure
        
        3 more items...
        
        force attraction between earth and an object
        
        3 more items...
        
        formula
        
        1 more item...
        
        forcemeter
        
        3 more items...
        
        SI unit of force is newton (N)
        
        we only can see the the effect
        
        invisible
        
        pushing or pulling action
        
        ray model of light
        
        light
        
        refraction
        
        3 more items...
        
        it has a speed of about 300 million metres per second
        
        reflection is the bouncing off of the light from an object
        
        4 more items...
        
        shadow
        
        2 more items...
        
        light travels in straight lines along paths which are called light rays
        
        object that give out light energy are said to be luminous object
        
        it can travel through a vacuum (empty space)
        
        form of energy that enables us to see
        
        eclipse
        
        lunar eclipse
        
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        solar eclipse
        
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        total or partial blocking of sunlight when one celestial body [earth or moon] passes in between the sun and other celestial body
        
        electrical systems
        
        electtrolytes
        
        2 main electrolysis
        
        2 more items...
        
        liquid conductors of electricity
        
        resistance
        
        the ratio of the potensial difference across the component to the current passing through the component
        
        formula
        
        ressistence = voltage across component [ v ] : current through component [ I ]
        
        electricity
        
        measuring using instrument called ammeter
        
        current consists of moving charges
        
        easy to changed
        
        a form of energythat result from the flow of charged particles
        
        electrical comopnents
        
        parallel
        
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        series
        
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        properties of matter
        
        matterial measurement
        
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        state of matter
        
        3 more items...
        
        the density of a substance is its mass per unit volume
        
        1 more item...
        
        the equipment of measurement
        
        5 more items...
        
        mass
        
        2 more items...
        
        volume
        
        2 more items...
        
        five main groups of materials
        
        5 more items...
        
        unit
        
        mutiples of the base unit
        
        1 more item...
        
        S.I. base unit ( systeme international )
        
        4 more items...
        
        numerical value
        
        science laboratory
        
        science lab symbol
        
        explotion substance
        
        toxic substance
        
        flammable substance
        
        irritable substance
        
        radioactiven substance
        
        corrosive
        
        u
        
        rules
        
        If any accident takes place, do not panic. Inform your teacher immediately and lab assistants for help.
        
        Hot apparatus take time to cool down. Allow time to cool them down and use tongs or heat protective gloves to pick them up.
        
        Examine glassware before using. Do not use chipped or cracked test tubes or beakers.
        
        Students must be made to wear safety goggles, lab coat, and shoes in the science laboratory. Loose clothes, sandals, and open hairs should be a strict NO in school science labs.
        
        Unused chemicals should never be put back in the original bottle. They must be disposed off as per the guidelines given by the lab assistant or science teacher.
        
        Before using any chemicals, read the label carefully. When mixing chemicals or conducting the experiment, keep the test tube containing the chemical away from your face, mouth, and body.
        
        It is very important to be alert and be cautious when in the science laboratory. Eating, drinking, playing pranks, using mobile phones, or listening to music should be strictly prohibited.
        
        Students must follow all the written and verbal instructions when conducting the science experiment. In case they do not follow anything, they must clarify it first.
        
        Students should never ever work in science lab in the absence of their teachers.
        
        do not enter a laboratory or carry out any experiments without supervision from your teacher
        
        what is it?
        
        systematic study of the natural and physical world through observation, experiment and analysis
        
        theory that help us to predict what might happen in the future
        
        helps to create machines and inventions which improve our surroundings and the quality of life. the use of scientific knowledge for practical purposes called technology
        
        the meaning or explanation why things happens in the universe
        
        not confined to the laboratory and shows itself in all aspects of our lives
      - Types of Energy
        
        Mechanical
        
        Kinetic
        
        Kinetic is the energy of motion, there are many forms of kinetic energy like vibrational, rotational, translational.
        
        Potential
        
        Energy is stored in an object to its position
        
        Hydroelectric
        
        Electricity is produced from generators driven by turbines that will transform the potential and kinetic energy from water that falls from a high altitude
        
        Hydraulic
        
        Water is stored at a high altitude so it has potential gravitational energy, later it falls to a lower level transforming that way to kinetic energy and it can be transformed into electric energy in a hydroelectric plant
        
        Tidal
        
        Is produced by the creation of the ocean waters during the rise and fall of tides, this is a renewable source of energy
        
        Thermal Energy
        
        This energy is created when the molecules of certain body begin to move rapidly, which generates heat. It can be considered a type of kinetic energy.
        
        Geothermal
        
        It is the thermal energy that is generated and that also can be stored in the Earth
        
        Biomass
        
        Solid biomass (ex:wood and garbage) can be burned directly to produce heat. Biomass can be converted into biogas or into biofuels such as ethanol and biodiesel. These fuels can then be burned for energy.
        
        Solar
        
        More energy from the sun falls on the earth than the energy is used all around the world. This solar energy allows to transform the sunlight to energy. The most commonly used for solar technologies are solar water heating, passive solar design for space heating and cooling, and solar photovoltaics for electricity.
        
        Eolic
        
        The Eolic energy si the conversion of energy in which turbines convert the kinetic energy of wind into mechanical or electrical energy that can be used for power.
        
        Nuclear Energy
        
        Nuclear energy is obtained by splitting the atoms of certain elements in order to set free the saturated energy. It was first used in the 1940's during the World War II. It is now used to control power generation and for the production of bombs.
      - SCIENCE revision
        
        Chapter 3.4- energy can be transformed
        
        GENERATING electricity
        
        wind generators use the wind to turn a turbine .
        
        the kinetic energy of the wind is transferred to kinetic energy of the turbines.
        
        1 more item...
        
        when energy is changed from one to another, we say it has been transformed.
        
        energy can also be generated from wind, water, coal. Etc. The energy made from all this can be used to charge your phone, cook dinner, turn on a light. Etc.
        remember, energy may take different shapes and forms before you can use it.
        
        Chapter 3.5- energy cannot be created or destroyed.
        
        heat and sound waste energy
        
        since no system is 100% efficient, in most cases, the energy that is extra is transformed into heat and sound energy.
        
        when you drop a ball, it starts with gravitational potential energy, which is then transformed into kinetic energy when you drop it. when the ball hits the ground, it makes a noise. the larger the noise is the more sound energy was generated.
        
        1 more item...
        
        calculating the energy efficiency formula:
        
        efficiency: useful energy output divided by energy input multiplied by 100.
        
        if all the input energy was added together it would be the same as the output but the type of energy may change.
        
        energy cannot be created or destroyed. this is called the law of conservation of energy.
        
        Chapter 3.6- energy efficiency can reduce energy consumption
        
        techniques when constructing your house to make it energy effecient
        
        Insulators: keep the house warm/cool whichever you please.
        
        a veranda prevents the heat and light from the sun from shining on the walls. this is prevents the heat from being transferred to the walls, and then to the air inside.
        
        limiting the amount of windows facing the sun.
        
        opaque windows: do not light come in
        
        Chapter 3.3- moving objects have kinetic energy
        
        SOUND ENERGY
        
        energy is a type of kinetic energy.
        
        energy is needed to make sound
        
        vibrations can occur in gasses and even solid things such as speakers.
        
        sound is generated when things vibrate.
        
        if you are near a source of very LOUD sound, your body begins to vibrate
        
        ELECTRICAL ENERGY
        
        As the electrons try to move back together, the electrical energy they had when they separated, get's changed into light, heat or movement that we see in light bulbs, heaters or motors.
        
        during separation, this means they are in a state of excitement and are trying to get back together again.
        
        if the positive and negative charges are locked together in one area such as a wire, the separate charges can easily move back together.
        
        All substances are made up of positive and negative electrical charges that, when separated, have electrical energy.
        
        HEAT ENERGY
        
        for instance, an ice block feels cool because it takes away the thermal energy from our hands.
        
        this energy can be generated by friction , burning chemicals, electrical devices. Etc.
        
        Heat energy is more "scientifically" known as "thermal energy".
        
        LIGHT ENERGY
        
        the light we see is part of a larger group called electromagnetic radiation.
        
        this LARGE group includes; ultraviolet light, microwaves and x-rays.
        
        the main reason life exists on planet earth and not on any other planet is the fact that our atmosphere allows right amounts of the different forms of light energy coming from the sun to reach the surface.
        
        the study of light is called optics/
        
        we see a range of colors in the spectrum such as red, orange, yellow, green. Etc.)
        
        the energy moves in small pockets of energy called photons
        
        the energy of movement is scientifically called kinetic energy (KE)
        
        Chapter 3.1-energy can be transferred
        
        All objects have energy.
        
        energy transfers for entertainment
        
        both CS and DVD players need to transfer energy from the batteries to the wires.
        
        the energy is then transferred into laser light, enabling it to read the information stored on the CD or DVD.
        
        1 more item...
        
        where does energy go?
        
        most energy that is extra is used to power transportation vehicles.
        
        public transportation uses energy as well
        
        1 more item...
        
        electric cars are being designed to use energy stored in batteries,rather than using patrol and at the same time making the wheels turn.
        
        where does energy come from?
        
        all of the energy on earth comes from one source: the sun
        
        the plants on earth absorb the energy from the sun in a process called photosynthesis.
        
        1 more item...
        
        examples of objects having energy
        
        stretched objects
        
        objects high off the ground
        
        moving objects
        
        when energy is passed from one object to another, it is said to be transferred.
        
        energy CANNOT be created or removed.
        
        energy is referred to as the ability to do WORK
        
        chapter 3.2 - potential energy is stored energy
        
        GRAVITATIONAL POTENTIAL ENERGY
        
        If we lift and object up into the air, it gains gravitational potential energy (GPE)
        
        The larger the mass and the larger the height, the more GPE the object gains
        
        the reason why objects that fall from a bigger distance develope a louder thud and can hurt more, is because as the object falls down, the objects GPE can be transformed into othe forms of energy.
        
        1 more item...
        
        potential energy is stored energy in objects that is waiting to be used.
        
        NUCLEAR ENERGY
        
        Nuclear energy involves the reaction at the center of the atoms.
        
        when atoms react in chemical reactions they usually release only small amounts of energy
        
        1 more item...
        
        CHEMICAL POTENTIAL ENERGY
        
        for instance, fuels such as natural gas and patrol provise us with energy as well.
        
        petrol has chemical energy stored in it.
        
        this energy, CPE, can be absorbed and released when a particle is triggered with another particle and causes a reaction.
        
        ELASTIC POTENTIAL ENERGY
        
        example is a trampoline for instance.
        
        a trampoline has the ability to "store" energy or "hold" i, for later use.
        
        1 more item...
        
        energy that is stored through stretching or squashing is called elastic potential energy.
        
        Science Required Practicals
        
        Chemistry
        
        Analytical Chemistry
        
        3 more items...
        
        Effect on concentration of rates of reaction
        
        2 more items...
        
        Measuring energy transfer
        
        6 more items...
        
        Distillation
        
        6 more items...
        
        Filtration
        
        3 more items...
        
        Measuring rates of reaction
        
        2 more items...
        
        Titrations
        
        4 more items...
        
        Paper Chromatography
        
        5 more items...
        
        Physics
        
        Ray Diagrams (light)
        
        6 more items...
        
        Waves on a string
        
        4 more items...
        
        Waves in a ripple tank
        
        6 more items...
        
        Thermal insulation - effectiveness of different materials
        
        4 more items...
        
        Measuring the effect of length on resistance
        
        4 more items...
        
        Acceleration
        
        4 more items...
        
        Leslie's Cube (IR radiation)
        
        2 more items...
        
        Making and calibrating a newtonmeter
        
        6 more items...
        
        Biology
        
        Link to all the official methods
        
        The effect of temperature on the decay of fresh milk
        
        5 more items...
        
        Measuring population size
        
        5 more items...
        
        The effect of light intensity on the rate of photosynthesis
        
        3 more items...
        
        Food tests
        
        4 more items...
        
        Effect of tropisms on germinating seeds
        
        5 more items...
        
        Effect of caffeine on human reaction times
        
        3 more items...
        
        Effect of antiseptics on growth of bacteria
        
        5 more items...
        
        Light Microscope
        
        3 more items...
        
        Effect of pH on rate of reaction of amylase enzyme
        
        5 more items...
        
        Effect of different conc. salt solutions on plant tissue
        
        5 more items...
        
        Science (Year 11)
        
        Scientific skills
        
        Experimental skills and investigations
        
        5 more items...
        
        Handling information and problem solving
        
        7 more items...
        
        Physics
        
        Forces
        
        Electricity and magnetism
        
        3 more items...
        
        Atomic physics
        
        1 more item...
        
        Waves
        
        2 more items...
        
        Kinetic model (particles)
        
        3 more items...
        
        Energy, work and power
        
        2 more items...
        
        Chemistry
        
        Acids, bases and salts
        
        Chemical reactions #
        
        3 more items...
        
        The Periodic table
        
        2 more items...
        
        Organic chemistry
        
        1 more item...
        
        Chemical analysis
        
        Industrial inorganic chemistry
        
        Quantitative chemistry
        
        Planet Earth
        
        Biology
        
        Plants
        
        3 more items...
        
        Cells
        
        2 more items...
        
        Inheritance # #
        
        Biological molecules
        
        4 more items...
        
        Humans and Mammals
        
        3 more items...
        
        Electrostatic
        
        Coulomb's Law
        
        This law states that
        
        The force of attraction or repulsion between 2 point charges is directly proportional to the product of the 2 charges and inversely proportional to the separation of the 2 charges.
        
        Electric field
        
        Gauss's Law
        
        This law states that the net number of electric field lines crossing any closed surface in a outwoard direction is numerically equal to the net total charge whithin that surface.
        
        What is this?
        
        R is the distance from the charge Q**
        
        The metric unit for the electric field intensity is ( newton per coulomb N/C)
        
        It said to exist in a region of space in which an electric charge will experience an electric force.
        
        Electric Potential
        
        Potential Reference at Infinity
        
        The general expression for the electric potential as a result of a point charge Q can be obtained by referencing to a zero of potential at infinity.
        
        Potential energy can be defined as the capacity for doing work which arises from position or configuration.
        
        For example, if a positive charge Q is fixed at some point in space, any other positive charge which is brought close to it will experience a repulsive force and will therefore have potential energy.
        
        First Law of Electrostatic
        
        This law states that
        
        "Like charges repeal each other and unlike charges attract each other".
        
        What is the definition of electrostatic?
        
        Is the science that treats charges at rest
        
        Physics
- - - - Cause and Effect
        
        observed in every aspect of physical phenomea
        
        essential for recognizing and describing nature
        
        constantly occuring in physical systems
      - Physical Laws and Theories
        
        used to describe and predict the behavior of nature
      - Nature/The Universe is Mechanistic
        
        universe is predictable
        
        universe is made of elements and parts that creates structure
      - Conservation Laws
        
        certain quantities of natures never change
        
        they are never created or destroyed, or conserved
      - Matter and Energy
        
        rlly important and have percise meanings and quantities physics
        
        basic in structure and nature of universe
      - Size and Scale
        
        used to describe subatomic particles to vast space
        
        used to distinguish of the size and scale of the universe
      - Consistency in the Universe
        
        same laws exists for the behavior of nature exists the same for the entire nature
        
        aka, one law for one part of the universe can be described for all of teh universe
    - - physics use models to describe phenomena
        
        systems are phys. interacting components or particles of an observation
        
        models is a representation or description of the structure or workings of a object, system, or concept
        
        models can take the form of a mathematical equation
        
        how they are made
        
        next, scientists remove parts of the system taht is note needed
        
        first, a simple model of one part of the system is made
        
        then, physicists merge those systems together to create more comprehensive models
      - Models can build hypotheses
        
        models can be used to judge if a hypothesis is plausible or testable
        
        hypothesis is a reasonable argument for an observation that can be proven through experiments and models
      - Models help guide experimental design and make predictions in new siturations
        
        models can reveal where experiments or experiments go wrong, and can be revised to be better
        
        hypotheses must be tested in a controlled experiment, where each factor is tested and compared to a control group
    - - Engineering
        
        Exploitation of Nature
        
        need to manipulate nature for human needs
        
        Application of Scientific Research
        
        need analyze nature to create a human goal
        
        Need to know how nature works
      - Science
        
        Pure Research
        
        human factor , such as 'will this research harm people, is excludec
        
        ones or others personal beliefs should not effect research
        
        Acquisition of Scientific Knowledge
        
        collecting, analyzing, and interpreting experimental data
        
        conducting experiments
        
        making observations of natural phenomena
      - Technology
        
        Ethics
        
        debate if technology is beneficial to humans or not
        
        believed it should always be used for the common good
        
        Consequence of Science and Engineering
        
        Engineering=creative thinking and desire to use nature for human purposes
        
        Science=scientific research is used dev. technology
    - - Areas within Physics
        
        Thermodynamics
        
        heat and temp. like melting and freezing processes, engines, and refigerators
        
        Optics
        
        behavior and properties of light
        
        mirrors, lenses, color, astronomy
        
        Electromagnetism
        
        electrical charge, circuitry, permanent magnets, electromagnets
        
        electricity, magnetism, and light
        
        Quantum Mechanics
        
        the atom and its parts
        
        behavior of submicroscopic particles
        
        Vibrations and Wave phenomena
        
        springs, pendulums, sound
        
        specific types of repetitive motions
        
        Relativity
        
        particle collisions, particle accelerators, nuclear energy
        
        particles moving at any speed, including very high speeds
        
        Mechanics
        
        falling objects, friction, weight, spinning objects
        
        motions and causes; interactions between objects
      - Goals
        
        use a small number of concepts, equations, and assumptions to describe phys. world
        
        to make predictions about a broad range of phenomea
  - - - Physics equations
        
        Weight = mass x gravitational field strength
        
        Work done = force x distance
        
        Force applied to a spring = spring constant x Extension
        
        Distance travelled = speed x time
        
        Acceleration = change in velocity / time
        
        Resultant force = mass x acceleration
        
        Momentum = mass x velocity
        
        Kinetic energy = 0.5 x mass x (speed)²
        
        Gravitational potential energy = mass x gravitational field strength x height
        
        Power = Energy transferred / time
        
        Power = work done / time
        
        Efficiency = useful output energy transfer / total input energy transfer
        
        Efficiency = useful power output / total power input
        
        Wave speed = frequency x wavelength
        
        Charge flow = current x time
        
        Potential difference = current x time
        
        Power = potential difference x current
        
        Power = (current)² x resistance
        
        Energy transferred = power x time
        
        Energy transferred = charge flow x potential difference
        
        Density = mass / volume
      - Magnetism & Electromagnetism
        
        Electric motors:
        A simple electric motor can be built using a coil of wire that is free to rotate between two opposite magnetic poles. When an electric current flows through the coil, the coil experiences a force and moves.
        
        Fleming's left hand rule:
        The direction of force - and therefore the movement of the wire - can be determined using Fleming's left hand rule.
        To do this:
        
        Spread out your left thumb, index finger, and second finger so they are al 90 degrees to one another.
        
        Point your index finger in the direction of the magnetic field.
        
        Point your second finger in the direction of the electric current.
        
        Your thumb will point in the direction of the movement.
        Thumb = Movement.
        Forefinger = Field.
        Second finger = Current.
        
        Magnetic field diagram:
        
        There are two poles on a magnet; north and south. These different poles can attract and repel, if opposite ends are brought together, they will attract. If the same side are brought together, they repel.
      - Waves
        
        Electromagnetic waves in order of size (largest to smallest):
        
        Radiowaves.
        
        Microwaves.
        
        Infrared radiation.
        
        Visible light.
        
        Ultraviolet.
        
        X-rays.
        
        Gamma rays.
        
        Typical Electromagnetic wave uses:
        
        Radio waves are used for television.
        
        Microwaves are used for cooking or mobile phones.
        
        Infrared waves are used for optical fibre communication.
        
        Visible light is obviously for seeing.
        
        Ultraviolet is used for detecting forged bank notes.
        
        X-rays are used for medical images of bones.
        
        Gamma radiation is used for killing cancer cells.
        
        Transverse & Longitudinal waves:
        In transverse waves, the oscillations are at right angles to the direction of travel and energy transfer. Light and other types of electromagnetic radiation are transverse waves. All types of electromagnetic waves travel at the same speed through a vacuum, such as through space.
        In longitudinal waves, the oscillations are along the same direction as the direction of travel and energy transfer. Longitudinal waves show area of compression and rarefaction.
        
        Properties of waves:
        Amplitude:
        As waves travel, they set up patterns of disturbance. The amplitude of a wave is its maximum disturbance from its undisturbed position. (Basically half the whole wave).
        Wavelength:
        The wavelength of a wave is the distance between a point on one wave and the same point on the next wave. It is easiest to measure from one crest to another.
        Frequency:
        The frequency of a wave is the number of waves produced by a source each second. It is also the number of waves that pass a certain point each second.
        
        Wave speed:
        v = f x λ
        
        V is the wave speed in m/s.
        
        f is the frequency in Hz.
        
        λ (lambda) is the wavelength in metres, m.
      - Forces
        
        Scalar and Vector quantities:
        The direction that an object is travelling is important when describing its motion. However, direction is not important for some quantities.
        A scalar quantity is a quantity in which direction is not important. All that matters is its magnitude.
        A vector quantity is a quantity in which direction is important
        
        Conservation of momentum:
        As long as no external forces are acting on the objects involved, the total momentum stays the same in explosions and collisions. We say that momentum is conserved
        
        Momentum:
        A moving objet has momentum. It is difficult to change the direction of movement of an object with a lot of momentum.
        p = m v
        
        p is the momentum in kg m/s.
        
        m is the mass in kg.
        
        v is the velocity in m/s.
        
        Acceleration:
        When an object moves in a straight line with a constant acceleration, you can calculate its acceleration if you know how much its velocity changes and how long this takes.
        a = (v - u) / t
        
        a is the acceleration of the object in m/s².
        
        v is the final velocity in m/s.
        
        u is the initial velocity in m/s.
        
        t is the time taken in seconds, s.
        
        Thinking, braking, and stopping distance:
        Thinking distance is the distance traveled when the driver realises he needs to brake and actually braking.
        Factors that may increase the thinking distance:
        
        Greater speed.
        
        Tiredness.
        
        Alcohol and drugs.
        
        Distractions.
        
        Braking distance is the distance taken to stop once the brakes are applied.
        Braking distance can be increased by:
        
        Greater speed.
        
        Poor road conditions.
        
        Car conditions.
        
        Newton's three laws:
        1st Law:
        States that objects with balanced forces acting on them will stay at rest or stay in constant motion.
        2nd Law:
        States that when an unbalanced force acts on an object;
        
        The direction of the objects acceleration is the same as the unbalanced force,
        
        The magnitude of the objects acceleration varies in direct proportion with the size of the unbalanced force,
        
        The magnitude of the objets acceleration varies inversely with the mass of the object.
        
        3rd Law:
        States that every action has an equal and opposite reaction.
        
        Velocity:
        The velocity of an object is its speed in a particular direction. Acceleration is a change in velocity, this means that an object accelerates if:
        
        Its speed changes.
        
        Its direction changes.
        
        Both its speed and direction change.
        
        Speed:
        The speed of an object tells you how fast or slow it's moving. To work out speed, the following two things must be known:
        
        The distance travelled.
        
        The time taken to travel that distance.
        
        Speed = Distance / Time
        
        Distance & Displacement:
        Displacement is the distance travelled in a straight line. It has both direction and size.
        
        Forces and elasticity:
        A force acting on an object may cause the shape of an object to change. Elastic objects can store elastic potential energy if they are stretched. For example, this happens when a catapult is used.
        
        Power:
        Power is a measure of how quickly work is being down and so how quickly energy is being transferred. Power is measured in watts (W).
        Power = Work done / Time
        
        Work done & energy transfers:
        Work done and energy transferred are measured in joules (J). The work down on an object can be calculated if the force and distance moved are known.
        Work done = Force x Distance
        
        Resultant forces:
        
        A stationary object remains stationary of the sum of the forces acting upon it is zero.
        
        A moving object with a zero resultant force keeps moving at the same speed and in the same direction.
        
        If the resultant force sting on an object is not zero, a stationary object begins to accelerate in the same direction as the force.
        
        A moving object speeds up, slows down, or changes direction.
        
        Gravity:
        Gravity is a force that attracts objects towards each other. Any object with mass exerts a force of gravity. The greater the mass, the greater the force. The force of gravity between two objects decreases as the objects move further apart.
        
        Pulls objects on Earth towards the centre of the planet.
        
        Holds the Earth's atmosphere in place.
        
        Holds all the components of the solar system in orbit around the Sun.
        
        Holds all the components in the galaxy together.
        
        Contact and non-contact forces:
        Non contact forces are forces that act between two objects that are not physically touching each other. An example of this could be magnets or gravity.
        Contact forces are forces that act between two objects that are physically touching each other. An example of this could be a box on a table, or pen on paper.
    - - Skeletal System
        
        The muscular system helps the skeletal system move witht the help from volentary muscles.
        
        The skeletal system helps protect the lungs from injuries. The lungs are protected by the ribs.
        
        Protects the fragile circulatory system.
        
        Helps protect vulnerable organs from injuries
        
        Provides calcium that is essential for the proper functioning for the nervous system.
        Skull protects the brain from injuries.
      - Muscular System
        
        The cardiac muscles around the outside of the heart involuntarily contract making the heart able to pump.
        
        Receptors in muscles provide the brain with information about movement
        
        The disgestive system needs involentary muscles to churn the food into the stomach periodically than getting pushed by the involuntary muscles down the intestines
        
        Gas exchange occurs when oxygen is pulled into the lungs by the external intercostal muscles between the ribs helping the volume increase
        
        The muscular system helps the skeletal system move witht the help from volentary muscles.
      - Nervous System
        
        Provides calcium that is essential for the proper functioning for the nervous system.
        Skull protects the brain from injuries.
        
        Brain monitors the respirtatory volume and blood levels and the brain regulates the respiratory rate
        
        Maintain the blood brain barrier
        Receptors send information to the brain about blood pressure
        
        Controls the tone of the digestive tract. Controls the muscles for eating and elimination
        
        Receptors in muscles provide the brain with information about movement
      - Digestive System
        
        Helps protect vulnerable organs from injuries
        
        Needs the digestive system to distributed the nutrients from the food digested into the blood to provide to the body through blood
        
        The disgestive system needs involentary muscles to churn the food into the stomach periodically than getting pushed by the involuntary muscles down the intestines
        
        Controls the tone of the digestive tract. Controls the muscles for eating and elimination
        
        The muscles need oxygen to function. The muscles around the stomach contract churning food and the intestines push food down.
      - Respiratory System
        
        Oxygen is pulled into the lungs than transferred into the blood going to the heart where its pumps the oxygenated blood throughout the body
        
        Brain monitors the respirtatory volume and blood levels and the brain regulates the respiratory rate
        
        The muscles need oxygen to function. The muscles around the stomach contract churning food and the intestines push food down.
        
        Gas exchange occurs when oxygen is pulled into the lungs by the external intercostal muscles between the ribs helping the volume increase
        
        The skeletal system helps protect the lungs from injuries. The lungs are protected by the ribs.
      - Circulatory System
        
        Needs the digestive system to distributed the nutrients from the food digested into the blood to provide to the body through blood
        
        Maintain the blood brain barrier
        Receptors send information to the brain about blood pressure
        
        Oxygen is pulled into the lungs than transferred into the blood going to the heart where its pumps the oxygenated blood throughout the body
        
        The cardiac muscles around the outside of the heart involuntarily contract making the heart able to pump.
        
        Protects the fragile circulatory system.
- - - - Physics Paper 1
        
        Atomic structure
        
        Types of radiation:
        Nuclear radiation comes from the nucleus of an atom. Substances that give out radiation are said to be radioactive. There are three types of radiation:
        
        Alpha
        
        Beta
        
        Gamma
        
        Radiation can be absorbed by substances in its path. For example, alpha radiation travels only a few centimetres in air, beta radiation travels tens of centimetres in air, while gamma radiation travels many metres. All types of radiation become less intense the further the distance from the radioactive material, as the particles or rays become more spread out,
        
        Alpha particle scattering experiment:
        A scientist called Rutherford designed an experiment to test the plum pudding model. It was carries out by his assistants Geiger and Marsden. A beam of alpha particles were aimed at a very thin gold foil and their passage through the foil were detected. The scientists expected the alpha particles to pass straight through the foil, but something else also happened.
        Some of the alpha particles emerged from the foil at different angles, and some even came straight back. This meant that the positively charged alpha particles were being repelled and deflected by a tiny concentration of positive charge in the atom.
        
        Plum pudding model:
        An early model about the structure of the atom was called the plum pudding model. The atom was imagined to be a sphere of positive charge with negatively charged electrons dotted around inside it like plums in a pudding. An experiment carried out in 1905 showed the plum pudding model could not be correct.
        
        Isotopes:
        Isotopes are atoms of an element with the normal number of protons and electrons, but different numbers of neutrons. Isotopes have the same atomic number, but different mass numbers. The different isotopes of an element have identical chemical properties. However, some isotopes are radioactive.
        
        Structure of the atom:
        At the centre of an atom is a nucleus containing protons and neutrons. Electrons are arranged around the nucleus in energy levels or shells.
        
        Alpha radiation is the least penetrating. It can be stopped (or absorbed) by a sheet of paper.
        Beta radiation can penetrate air snd paper. It can be stopped by a thin sheet of aluminium.
        Gamma radiation is the most penetrating. Even small levels can penetrate air, paper or thin metal. Higher levels can only be stopped by many centimetres of lead, or many metres of concrete.
        
        Half life:
        The time taken for the radioactivity of an isotope to half its original value.
        
        Hazards:
        Radioactive materias in the environment do expose people to risks.
        
        The radiation from the material can damage the cells of the person directly. This is damage by irradiation.
        
        Some of the radioactive material can be swallowed or breathed in. While inside the body, the radiation it emits can produce damage. This is damage by contamination.
        
        Particle model of matter
        
        Pressure:
        Pressure x volume = constant
        pV= Constant
        
        Temperature on gases:
        Imagine a gas is trapped inside a container. If the gas is heated, the particles will gain kinetic energy which will make them move faster. This causes the force on the walls of the container to increase and so the pressure increases.
        
        Density:
        Mass / volume
        p=m/v
        
        Specific latent heat:
        The specific latent heat of a substance is a measure of how much heat energy is needed to melt or boil. It is the energy needed to melt or boil 1 kg of the substance.
        energy for a change of state = mass x specific latent heat
        E=mL
        
        Different changes of state:
        A substance must absorb heat energy so that it can melt or boil. The temperature of the substance dos not change during melting, boiling, or freezing, even though energy is still being transferred.
        
        Electricity
        
        The national grid:
        The national grid transmits power via electricity towers across the country, you can normally see these dotted around the various landscapes. They use things called transformers.
        A transformer is an electrical device that changes the voltage of an alternating current (ac) supply, such as the mains electrical supply. A transformer changes a high-voltage supply into a low-voltage one, or vice versa.
        
        Energy transferred:
        Power x time
        E = P t
        Charge flow x potential difference
        E = Q V
        
        Power:
        potential difference x current
        P = V I
        (Current)² x resistance
        P = I² R
        
        Potential difference:
        Current x resistance
        V = I R
        
        Series circuits:
        Components that are connected one after another on the same loop of the circuit are connected in series. The current that flows across each component connected in series is the same.
        Parallel circuits:
        Components that are connected on separate loops are connected in parallel. The current is shared between each component connected in parallel. The total amount of current flowing into the junction, or split, is equal to the total current flowing out. The current is described as being conserved.
        
        Series
        
        Parallel
        
        Electricity mains
        Electricity mains supply have a frequency of 50Hz and is about 230V.
        
        Inside a plug
        There are three main wires in a plug. The blue, striped, brown (From left to right).
        
        Blue is the neutral wire.
        
        Striped is the earth wire.
        
        Brown is the live wire.
        
        There is a fuse on the right hand side of the plug which breaks the circuit if too much current flows.
        
        Electrical charge:
        charge flow = current x time
        Q = I t
        
        Energy
        
        Kinetic Energy:
        0.5 x mass x (speed)²
        Ek = ½mv²
        
        Energy efficiency:
        Useful output energy transfer / total input energy transfer
        Useful power output / total power input
        
        Wasted Energy:
        Energy that is 'wasted', like the heat energy from an electric lamp, does not disappear. Instead, it is transferred into the surroundings and spreads out so much that it becomes very difficult to do anything useful with it.
        Useful Energy:
        Energy that is used in a way where the wasted energy is collected and then used for another purpose.
        
        Power:
        Energy transferred / time
        P = E/t
        Work done / time
        P = W/t
        
        Change in thermal energy:
        Mass x specific heat capacity x temperature change
        ΔE = m c Δ Ø
        
        Gravitational potential energy:
        Mass x gravitational field strength x height
        Ep = m g h
        
        Elastic potential energy:
        0.5 x spring constant x (extension)²
        Ee = ½ke²
- - - - reactivity and electron movement
      - noble gasses
      - halogens
      - alkali metal
    - - meaning of atomic number, proton number and mass number
      - molecules made of atoms
      - isotopes, focus on definition
      - charge and relative atomic masses of proton, neutron and electron
      - composition of nucleus
  - - - Energy stored in a spring
      - using hooke's law to predict extensions and forces in simple samples
      - Make sure the concept of direct proportionality is emphasised
      - Hooke's law
      - Elastic and inelastic changes of shape
      - Using equipment: Focus on parallax error, use of pointer, clamping ruler, calculate extension but measure lengths etc.
      - Independent and dependent variables
      - Drawing graphs, including dealing with anomalies
      - Typical graphs of F vs e for wires, springs and elastic bands.
      - these changes of shape are normally quite small for a wire, but if we use a spring we can easily measure them.
      - the idea of a charge of shape measured by the extension from the original length
      - the concept of applying a tensile force to and object and it streching
    - - measurements of density of:
        
        gas
        
        irregular object
        
        liquid
        
        regular object
      - stress that density is a quality of a material under certain conditions, not a feature of mass or volume
      - rearrangements and simple calculations
      - typical values
      - units kg/m^3 and g/cm^3 and conversions between the two
    - - practical techniques
        
        introduce the concept of repeating and averaging to minimise errors (in cases when readings vary) and help spot anomalies
        
        parallax error measure at 90 degrees, bend down in line with subject and ruler (human error)
        
        zero error=start from zero, or take away that value (systematic error)
      - units of area and volume (including conversion)
      - standard prefixes & conversions
      - standard form
      - significant figures
      - SI units
    - - emphasise the emmision of em radiation due ti change in electron position
      - ionisation by addition or removal of electron
      - atom neutrality resulting from charge balance
      - emphasis electron orbit
    - - universe made of matter
      - isotopes focus on definition (versions of the same element but with different amounts of neutrons.
      - meaning of atomic number, proton number, mass number and nucleon number
      - charge and relative masses of proton, neutron, electron
      - use symbols like ones on periodic tables and terms such as carbon-13 to describe a particular particle
      - composition of nucleus
      - size of atom and nucleus including order of magnitude
        
        size of nucleus average=10^ -14 meters size of atom normally 10^ -10
      - atom as tiny nucleus surrounded by electron cloud
      - what defines an element
      - molecules made of atoms
      - smallest unit of matter is the molecule
- - - - All have pros and cons
      - Carbon dioxide can be captured and stored
      - Sulphur can be removed removed from the fuel before it is burned
    - - Will last longer than others
  - - - Produced inside the earth
        
        Radioactive processes
        
        Heat the surrounding rock
      - In some parts of the world, hot water comes naturally to the surface
        
        Used directly to heat buildings
      - Deep holes drilled in volcanic areas
        
        Cold water pumped onto hot rocks
        
        Water is heated and returns as steam
        
        Steam used to drive turbines
        
        Electricity produced
    - - Solar Power Tower
        
        Thousands of mirrors to reflect sunlight onto solar cells
      - Travels through space as electromagnetic radiation
        
        Solar cell transfers light energy into electrical energy
        
        Only a small amount
        
        useful for small devices
        
        Large numbers of solar cells = solar panel
  - - - When demand is low, water si returned to the resevoir and stored
      - Demand is met using (non)renewable sources
      - 'Base load Demand'
    - - Gas fired power stations are the fastest
      - Nuclear poer takes the longest
    - - Between summer and winter
      - During the day
  - - - Increased by Step Up Transformers before being transmitted across the grid
        
        Reduced by Step Down Transformers at sub stations
        
        Would be dangerous otherwise
        
        Reduces voltage to 230V
        
        Makes the system more efficient
        
        Reduces wasted energy in cables
      - Power stations
        
        25, 000 V
      - Grid volatge
        
        More than 132,000 V
    - - Close to homes
      - In towns
    - - Connects power stations to buildings
  - - - Water
        
        Leftover energy is pumped back to the resevoir
        
        At times of low demand
        
        Not wasted
        
        Wave power
        
        Use of the movement of waves
        
        Drives a floating turbine
        
        Turns a generator
        
        Power delived to a grid system cable
        
        Hydroelectric power
        
        Water collected in resevoir
        
        Flows downhil
        
        Turns turbines at bottom of hill
        
        Energy from falling water, tides or waves
      - Can never be used up
        
        Unlike fossil fuels or nuclear power
      - Tides
        
        Use of the tide going in and out
        
        Water at each high tide can be trapped
        
        Drives turbines when released
      - Wnd
        
        Wind passing over blades
        
        Rotate
        
        Drive generator
        
        Wind and water can directly tuen turbines
  - - - Water heated to make steam
        
        drives a turbine
        
        coupled to a generator
        
        makes electricity
    - - Gas
        
        Gas can directly turn the turbine #
      - Oil
      - Coal
    - - Uranium or plutonium is used
        
        Nucleus goes under nuclear fission
        
        releases more energy per kilo than fossil fuels #
      - No greenhouse gases
    - - renewable
- - - - Not easily broken
    - - can be drawn into wires
    - - solid at room temperature except mercury
    - - shiny when cut, scratched, or polished
    - - excellent conductors of electricity and heat
    - - can be hammered into shape
  - - - Atoms mixed not chemically bonded together
  - - - Bases = OH-
    - - Acid + base (hydroxide) = salt + water
      - Acid + base (carbonate) = salt + water + carbondioxide
      - Reactants
      - Products
      - Metal + acid = Salt + hydrogen
      - Metal + water = metal hydroxide + hydrogen
      - Metal + oxygen = metal oxide
  - - - Valance shell
        
        Electron configuration
    - - Neutrons
        
        0
      - Protons
        
        +