P1 - Energy & P3 - Particle Model of Matter
L1 and L2 - Converting Simple Units
There are 1000mm in a meter and 1000mg in a kilogram. There are 1000 milliseconds in a second.
Mega - Million
Giga - One thousand million
L3 - Energy Stores and Systems
There are several energy stores: these include kinetic, gravitational potential, elastic potential, sound, heat, chemical, electrostatic, magnetic and nuclear.
Energy can be transferred through mediums such as mechanical transfer, work done when current flows, thermally and radiation.
L4 - Power
Power is defined as the rate of energy transfer or the rate at which work is done.
E = P x t
P = I x V
P = I^2 x R
L5 - Efficiency
Within energy transfer diagrams; useful energy is indicated by a direction that is parallel to the input energy's direction. Its magnitude is shown by the width of the arrow. Waste energy is shown to migrate away from the useful energy output.
Efficiency = (Useful power out / Total power in) x 100
Efficiency = (Useful energy out / Total energy in) x 100
Efficiency is described as how good a device/system is at producing a maximum useful output and a minimum waste output.
L6 - GPE
Gravitational potential energy increases the further an object is away from the Earth's surface (provided the object is in the atmosphere). Henceforth, the higher up an object is, the more kinetic energy it will generate and the faster it will hit the ground.
Most gravitational potential energy (Ep) is converted to kinetic energy.
Ep = h x g x m
GPE = Height x Gravitational Field Strength x Mass
L7 - Kinetic Energy
Ek = 0.5(m(v^2))
Kinetic Energy = 0.5(Mass(Velocity^2))
L8 - Craters
The size of a crater is determined by the kinetic energy held by the body that hits the surface.
Resolution is the smallest possible increment that a variable can be measured in with a piece of equipment.
Uncertainty is defined as half the resolution + or - the result you have recorded.
L11 - Elastic Potential Energy
F = ke
Ee = 0.5(k(e^2))
L12 - Energy Resources
There are several methods of obtaining energy, these mediums include:
- Fossil fuels (Non-renewable)
- Nuclear (Non-renewable)
- Bio-fuel (Renewable)
- Wind (Renewable)
- Wave (Renewable)
- Hydroelectric (Renewable)
- Geothermal (Renewable)
- Solar (Renewable)
A renewable resource is a resource that can be used and replenished simultaneously.
Methods:
- Fossil fuels - coal, oil or gas is burnt and used to drive turbines.
- - Nuclear - Enormous amounts of energy are generated through nuclear fission, heating water, converting it to steam and driving turbines.
- - Bio-fuels - Organic matter such as plant or animal material is burnt, driving turbines.
- - Wind - Wind is used to drive turbines directly, transferring kinetic energy to electrical energy.
- - Wave - Wave machines use kinetic energy of the waves to power electrical generators.
- - Hydroelectric - Water from behind a damn has gravitational potential energy, when it is allowed to rush down the damn, the kinetic energy possessed by the water is used to drive generators.
- - Geothermal - Hot water and steam from underground is used to drive turbines, generating electrical energy.
- - Solar - Energy provided by nuclear fusion occurring within the sun. Solar panels convert this into electrical energy.
Pros and Cons:
- Fossil fuels - N/A | Produces carbon dioxide when burnt as well as sulfur dioxide which causes acid rain.
- - Nuclear - No harmful or polluting gasses produced (also incredibly efficient) | an accident can cause environmental decimation.
- - Bio-fuels - Renewable | will release greenhouse gasses when burnt.
- - Wind - No harmful, polluting gasses produced, no fuel costs | If there is no wind, no energy will be generated, can 'spoil the view'.
- - Wave - Extremely reliable, no harmful gasses produced | Difficult to scale up, potential to destroy habitats.
- - Hydroelectric - Extremely reliable, no harmful gasses produced | Difficult to scale up, dams have the potential to destroy homes and farmland.
- - Geothermal - No harmful, polluting gasses produced, no fuel costs | Not suitable in all areas.
- - Solar - No fuel costs, no harmful or polluting gasses produced | Expensive and inefficient, will not work with minimal light exposure (night).
L14 - Reducing Heat Loss
E = m c Δθ
Change in thermal energy = mass x specific heat capacity x change in temperature
P3 - L1&L2 - Calculating Density
Density refers to the amount of mass (number of particles) in a given volume. Density can be calculated with the the equation:
Density = Mass / Volume
ρ = m / V
Mass can be found using an electronic balance; volume of an irregular solid can be found via the use of a eureka can: slowly place the solid into the eureka can (filled with water), collect the volume of water that is displaced by the object, this is the solids volume.
P3 - L3 - Changes in State
When a change in state occurs, energy provided does not add to the kinetic store of the object but instead the potential store, this will produce a plateau where the temperature of the object does not seem to increase.
Stearic Acid Practical: Method:
- First, place the solid strearic acid in a test tube within a beaker containing water. A thermometer should be placed within the test tube and the apparatus should be perched above a Bunsen burner in a tripod.
- - Next, the Bunsen burner should be turned on and henceforth the water heated, this will melt the stearic acid.
- - Once the acid has completely melted, begin a timer and turn the Bunsen burner off. Record the temperature of the acid every minute until it reaches 40 degrees.
A plateau will be seen when drawing the graph for a cooling curve, this graph is present because the formation of bonds in the object releases energy, this counteracts the energy being lost and the temperature plateaus.
P3 - L4 - Internal Energy
Temperature is proportional to the average kinetic energy of particles in a substance.
The total energy stores in the particles of a substance is known as its internal energy. This is the energy caused by the individual particles motion and position. Internal energy is the sum of a particles kinetic energy and potential energy.
During a state change, internal energy will still increase but the temperature will not.
P3 - L5 - Specific Heat Capacity
Three factors that affect how easy it is to heat up a substance are: the mass of the substance, the type of substance and the change in temperature.
E = mcΔθ [Joules] = [kg] x [Joules/kg°C] x [°C]
Specific heat capacity is the amount of energy that is required to raise 1kg of a substance by 1°C
P3 - L6 - Specific Latent Heat
Specific latent heat of vaporisation and specific latent heat of fusion are both a measure of the energy required to change the state of 1kg of a given type of substance.
E = m x L
Energy = Mass x Specific Latent Heat
[Joules] = [kg] x [Joules/kg]
Specific Latent Heat of Water: Method:
- Note down the power of the kettle you are using.
- - Place the kettle on an electronic balance and tare it (revert mass to 0). Then, pour a given volume of water (at room temperature) into the kettle and record the initial mass.
- - Begin a timer and turn the kettle on, when a given amount of time has passed, turn the kettle off and record the final mass of water.
- - Subtract the initial mass of water from the final amount.
- - Find the amount of energy used using "Energy = power x time".
- - Divide the energy used by the mass of the water to find the specific latent heat.
P3 - L7 - Pressure in Gasses
Gas particles move at random speeds in random directions; when they collide with the walls of a container they exert a force on the wall. Pressure is equal to the force exerted by these particles on a given area.
Pressure = Force / Area
P3 - L8 - Pressure in Gasses Pt.2
Pressure x Volume = Constant [Pascals] x [m^3] = Constant
Pressure in a gas can be increased via: decreasing the volume of the container, increasing the volume of gas in the container and increasing the temperature of the system.