Energy Transfer
pretty much everything you need to know on this topic for GCSE, includes some equations
- Created by: ukgamer321
- Created on: 22-04-14 20:55
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- Energy Transfer
- Particles
- Solids
- set shape
- can't be compressed
- joined by bonds
- vibrations can pass through
- Liquids
- Can be poured
- takes the shape of the container
- can't be compressed
- Gas
- Not bonded
- can be compressed
- Why? - particles are so spread out so they can be compressed (squashed) together easily. While in solids and liquids the particles are more compact
- Solids
- Evaporation- when a liquid turns into a gas
- Best conditions for evaporation
- big surface area
- warm temperature
- dry
- windy
- not humid
- Our hands fell cold when using hand gel because the gel takes the heat energy away from our hands
- A liquid cools down when it evaporates because
- 1. particles with the most energy evaporate
- 2. they have enough energy to overcome the forces from other particles
- 3. the average energy of the ones left behind decreases so the temperature decreases
- Best conditions for evaporation
- Condensation- when a gas turns into a liquid
- 1. gas cools so particles slow down ,lose kinetic energy and are pulled together
- 2. as the temp drops the particles get close enough together that condensation occurs
- Thermal Radiation/ Infa-red
- Matt/ black surfaces
- good absorbers
- good emitters
- Shiny/silver surfaces
- good reflector
- poor emitter
- Using thermal Radiation
- can travel through a vacuum
- travels in straight lines
- travels at the speed of light
- matt surfaces are the best at emitting infa-red radiation
- Matt/ black surfaces
- Convection
- 1. particles gain energy, move apart and become less dense so they rise
- 2. As the heated particles move away from the heat source, they cool, become closer together and fall
- Conduction
- Solids are the best conductors because the particles are closer together
- 1. particles closest to heat source begin to vibrate more, which passes on the energy to surrounding particles
- 2. These surrounding particles also begin to vibrate faster until all particles are vibrating faster and the solid expands
- Metals are good conductors because they have free electrons, which move where they want and pass on energy quicker
- Payback time- cost divided by saving
- Cost effective- total saving minus the initial cost
- The lower the U value, the better insulator the material is
- Specific Heat Capacity
- E=M x C x 0
- E= energy transferred in joules (J)
- M= mass in kg
- C= specific heat capacity in J/kg degrees C
- 0= temperature change in degrees C
- E=M x C x 0
- Heat Transfer
- Cavity Wall
- stops convection, radiation and conduction
- Loft
- stops conduction and radiation
- Draught proofing
- stops convection
- curtains
- conduction and radiation
- Cavity Wall
- Types of energy
- electrical
- whenever a current flows
- light
- sun, light bulbs
- sound
- noise
- kinetic
- movement
- thermal
- hot objects to cold
- gravitational potential
- anything that can fall
- elastic potential
- stretched springs, bands etc
- chemical
- foods and batteries
- electrical
- Particles
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