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Science Secondary 2 [Interactions] Part 1 - Coggle Diagram
Science Secondary 2 [Interactions] Part 1
Energy and Work Done
Energy is the ability to do work
in order for work to be done on an object, one must ensure that that there is athe oo force acting on the object AND the object must move inthe SAME DIRECTION as the force
Work is not ALWAYS done when a force is applied
forms of energy
Nuclear Energy
Sound Energy
Light Energy
Heat Energy
Kinetic Energy (moving things)
Potential Energy
Elastic potential Energy (Stretching items)
Chemical Potential Energy
Gravitational Potential Energy (Gravity)
Electrical Energy
Energy CAN BE converted from one form to another BUT CANNOT BE destroyed or created
sources of energy
Renewable
HydroElectric Energy
comes from water which makes electriciy from water but
if there is a flooding or the dam breaks, it will cause flooding of homes, habitats and farmlands
Solar Energy
come from sunlight that can be used to heat water that could be converted into electrical energy
no harmful effects on humans or the environment so its human and environmentally friendly
Geothermal Energy
come from hot rocks buried deep undergroud near the volcanic areas
uses
can heat homes and buildings and can also generate eletricity
but it can cause the power station to sink as it is too hot and could extractpoisonous substances like hydrogen sulfide from underground which may also affect the flow patterns of rain fall so it might not be friendly to humans and the environment
Wind Energy
uses wind to generate electricity which will be used from electricity to have light on homes
may cause deaths of birds and bats and people might get headaches and nausea due to the low frequency noise including infrasound
Biofuels
come from animals and plants like hyacinth and sugarcane
uses
obtain biodiesel fuels for motor vehicles
Produces carbon dioxide when burnt which cotributes to global warming so using fossil fuels are NOT evironmentally friendly
Nuclear Energy
not tested
Non - renewable
Fossil fuels
uses
Petrol for cars. Diesels for buses, taxis and lorries
made from dead plants and animals (take many years to form)
Produces carbon dioxide when burnt which cotributes to global warming so using fossil fuels are NOT evironmentally friendly
Sound
Take Note!
is all around us, movement of objects creates sound
must travel through a medium
caused by vibrations of matter
CANNOT be heard if there is NO MATTER!
CAN travel ONLY IN/THROUGH matters
relationships between matter and sound
Liquid
when they start to vibrate, they all start vibrate a little bit slower compared to the solid as the molecules are NOT PACKED AS CLOSELY AS A SOLID
Speed of sound on matter
solid = 5 000 m/s (metres per second)
gas = 330 m/s
liquid = 1 500 m/s
Gas
when they start to vibrate, they all start vibrate very slowlyas the molecules are FAR APART FROM ONE ANOTHER
Solid
when they start to vibrate, they all start vibrate very fast as the molecules are PACKED VERYCLOSELY TOGETHER
Humans can hear sound ranging from 20Hz to 20 000 Hz
the loudness of a sound DEPENDS on how big the vibrations in the medium are
Greater vibrations produce LOUDER sounds
How does sound vary?
Animals like rabbits and dogs can hear sounds that are too soft for the human ear to hear. This way, they could avoid dangers and predators
IRL (in real life) situations
if A is stuck in a lift, they will press the emergency button, ALERTING others that A is stuck in a lift and they need help
Speed of sound is distace over time taken or remember DST formula (the triangle) for speed
Hearing AIDS
are small devices that increase the loudness of sound
consists of an amplifier, microphone and a receiver, Powered by a battery
a hearing aid increases the volume the loudness of sounds by producing greater vibrations of air molecules
occurs when a vibrating object disrupts the air arund the it
the vibrating air molecules causes the structures within the ears to vibrate
the vibrations pass the sound energy to our brain and the brain translatesthe vibrations into information
The Human Ear
Consists of
Middle Ear
Anvil
Hammer
The three bones that help the vibrations to be transferred to the Inner ear
Eardrum
a flap of skin that vibrates according to the frequency of the sound
Stirrup
Ear Canal
a tube that channels the sound to the Eardrum
Inner Ear
cochlea
a shell shaped chamber
begins to vibrate according to the different frequencies which are then passed to the brain via the Ear nerves
ear nerves
receives electrical signals from the vibration of the cochlea. It then sends the signals to the brain which interprets the sound
Outer Ear
The cup-like flap that collects the sound
Sounds can differ in pitch and loudness
pitch
high
example
dentist drill at high speed / the squeaking of a mouse
cow mooing / sounds made by a large drum / a bass guitar
low
units; Hertz (Hz)
its the no. of cycles per second made by the vibrating source of sound is called the frequency of a sound
The higher the frequency, the higher the pitch....The lower the frequency, the lower the pitch
one hertz mean one cycle per second
overall, Larger instruments produce lower pitch and smaller instruments produce high pitch.
Uses of sounds in
animals
to commuicate and alert others bout something like danger
humans :
To warn / alert /alarm others bout something like danger
alarm clocks to wake up'
Entertainment Purposes
to entertain ppl like watching tv and listening to songs etc.
pleasing sounds
Sonar
like
gathering info about something
reflected sounds (like echoes) from the ocean floor can provide information about how deep a water body is; can be used to MEASURE the depth of water
Ultraasound and Technology
used to detect frequencies above 200 000Hz which the humans ear cannot hear
For doctors to observe fetuses in pregnant mothers. detect cancers and observe tumour in the body
To break kidney stones into smaller pieces so that it can be passed out of the body easily WITHOUT doing surgery
used to monitor blood flow in the veins and abnormalities within the Heart
Noises
units Decibels (dB)
can lead to hearing impairment due to burst eardrums
is excessive that MAY come from humans, animals and machines
can be unpleasant to our ears and annoy us like cats yowling at night
types of sounds and their noise / loudness
traffic on road = 80 dB
Motorcycle = 100 dB
normal convo = 40 to 60 dB
Library whisper = 20 to 30 dB
silence = 0dB
Pneumatic Road Drill = 120 dB
Jet engine/Rock concert 140 dB
Thunder close by = 160 dB
point which pain in the ears begin = 125 dB
Eardrum tissue destroyed = 180 dB
Effects of Heat and its transmissions
the degree of HOTNESS OR COLDNESS of something is
MEASURE BY ITS TEMPERATURE
Degree Fahrenheit
Kelvin (The SI unit for temperature)
Degree Celsius (common unit for temperature)
Applications of heat transfer in
Take Note!
the expansion of an object gives rise to large forces
Telephones and electricity cables
Raised on poles contract in cold weather. They may become taut and even snap. Hence, the wires and cables are hung loosely from pole to pole
MRT Railway Tracks
it can bend and twist due to expansion of hot weather. Hence, expansion gaps in the tracks provide space for the tracks to expand without any damage on hot days/weathers
Uses Of Expansion
Opening a jar
the lid of a jar can be opened when the lid is dipped inside warm water for a few minutes then can open. This happens due to expansion of the lid
Bimetallic strips
used on appliances that rely on teperature regulation. It consists of 2 different metals that expand at different rates when heated
Uses
Thermostats
keeps the temperature constant. Ovens and refridgerators are installed with thermostats to keep the temperature high and low, respectively.
HEAT FLOWS FROM a REGION OF HIGHER TEMPERATURE to a REGION OF LOWER TEMPERATURE
keeping buildings cool
in some countries, they dont face winter season which means its always hot there
uses of
Concretes
an insulator of heat so that heat from the sun or the surrounding DOES NOT MOVE EASILY THROUGH CONCRETE
Air-conditioners
cools the rooms in the buildings
Double gazing
are windows that have 2 sheets of glass WITH a layer of air TRAPPED between them. The AIR and GLASS are INSULATORS OF HEAT
Glass windows
Shiny windows reflects heat radiation and the glass is an insulator of heat
spacesuits
its design
Layers of insulating material
made of a special insulating material which PREVENTS HEAT FROM
CONDUCTING
INTO OR OUT OF THE SPACESUIT. Air is trapped between these layers which also helps in preventing conduction of heat
White outer layer
coloured in white in order to REFLECT RADIATION from the sun which prevents the astronaut from absorbing TOO MUCH RADIATION that heats up the body
helmet
made of special insulating material to prevent heat transfer through
CONDUCTION
vaccuum flask
the diff parts of the flask work together to keep a liquid hot
Silvered glass walls
walls are painted in silver so that radiation is reduced
vaccuum
created between the glass wallsby removing air. Conduction AND Convection CANNOT TAKE PLACE in a vaccuum
cap
usually made from an insulator of heat like Plastic
plastic or cork stopper
the mouth of the flask is stopped using an insulator of heat which also prevents heat loss through CONVECTION into the surroundings.
Movement of heat through the process of
Conduction
The process of heat transfer THROUGH a medium or material WITHOUT ANY MOVEMENT of the medium or material
conductors
materials that Conduct heat
Examples
conductors: Most metals and mercury liquid
are found in items such as cooking utensils and radiators
used whenever heat has to be quickly transferred from one place to another
the metal base of a frying pan is a good conductor of heat
Insulators: Wood, Rubber, asbetos, plastic, glass, water and air
used to reduce the amount of heat transfer
handles of cooking utensils are good heat insulators
insulators
materials that DONT coduct heat
Convection
The process of heat transfer of heat from one place to another by the movement of fluids
solids are better conductors of heat than liquids and gases
liquids and gases transfer heat through convection
takes place due to expansion of a fluid. when it is hot, its volume increases and its density decreases
Applications
Household ventilation, Electric Kettle
car radiators gets rid of heat mainly by
conduction and convection
Radiation
doesnt need the presence of matter
the transfer of heat in the form of waves from one place to another. It also doesnt need a medium for transmission
how a body radiates heat depends on
Total surface area of the body
The GREATERTHE AREA, the HIGHER the RATE OF RADIATION OR ABSORPTION
Temperature of the body
The HOTTER the body, the HIGHER the RATE OF RADIATION
The nature of the surface (texture and colour)
The DARKER and ROUGHER the surface, the HIGHER the RATE OF RADIATION OR ABSORPTION
TAKE NOTE!
(whether it is black, white or coloured; rough smooth or shiny)
uses of
good radiators of heat
bad radiators of heat
in real life
(colours)
house painted in bright colours keeps the house cooler than house with dark colours. This is because the BRIGHT COLOURS ABSORB
LESS
HEAT RADIATION.
dark coloured clothes make you feel warmer than wearing bright coloured clothes. This is because BRIGHT COLOURED CLOTHES ARE A
BAD ABSORBER OF HEAT RADIATION FROM THE SUN
.