P1 OCR

P1 OCR

Heat and Temperature
1. Energy is transferred from a hotter to a colder body.
2. Temperature is a measure of HOTNESS on an arbitrary scale, measured in DEGREES CENTIGRADE.
3. Energy is a measure of ENERGY TRANSFER on an absolute scale, measures in JOULES.
4. Energy is transferred when a substance changes temperature.
  1. The amount of energy transferred depends on the mass and the specific latent heat.
    1. Energy transferred = mass x specific latent heat
5. The amount of energy transferred depends on the mass, temperature change and specific heat capacity.
  1. energy transferred = mass x specific heat capacity x temperature change
Energy Transfer
1. Air is a good insulator and reduces energy transfer by conduction
  1. Conduction in a solid is by the transfer of kinetic energy
2. Trapped air reduces energy transfer by convection
  1. Convection currents are caused by changes in density
3. Energy saving in the home can be achieved by:
  1. Double glazing
  2. Cavity wall insulation
  3. Draught excluders
  4. Reflecting foil
  5. Loft insulation
  6. Curtains
  7. Careful design
4. Shiny surfaces reflect infrared radiation to reduce energy transfer
5. Energy transformations can be represented by diagrams
6. Efficiency = useful energy output (x100%) / total energy input
Waves Transfer Energy
1. Warm and hot objects emit infrared radiation
2. Infrared radiation is used for cooking
3. Microwaves can be used for cooking and communication when transmitter and receiver are in line of sight
4. Laser light is single colour and in phase
5. Laser light, visible light and infrared are all used to send signals along optical fibres by total internal reflection
6. Digital and analogue signals are used for communication
  1. Morse is a digital code
  2. Digital signals allow many signals to be transmitted at the same time
  3. Digital signals are clearer
7. Radio waves are used for communication
  1. Longer wavelengths diffract around obsticles
8. Radio waves, microwaves, infrared, visible light and ultraviolet are some of the waves in the electromagnetic spectrum
  1. The energy of the wave increases as the wavelength decreases
  2. All electromagnetic waves can be reflected, refracted and diffracted
  3. All waves have amplitude, frequency and wavelength: wave speed = frequency x wavelength
The Stable Earth
1. Earthquakes can travel through the earth
2. Different waves help us to find out about the inside of the earth
3. Exposure to ultraviolet radiation causes sun burn and skin cancer
4. Sunscreen and sunblock reduces damage caused by ultraviolet radiation
5. CFCs are causing the ozone layer to become thinner

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	Created by Hannah Fowkes about 11 years ago