1. Happens in solids, liquids and gases
2. Metals are good conductors
3. Gases and other non-metals are poor conductors
4. Poor conductors such as glass are called thermal insulators.

1. Only happens in liquids and gases
2. The flow of the liquid or gas due to convection is called a convection current
3. Convection is more important than conduction in liquids and gases.

1. Energy carried by waves
2. The sun radiators energy into space
3. The earth absorbs a tiny fraction of the energy radiated from the sun
4. Plants need sunlight for photosynthesis.

They detect thermal radiation (also called infra-red). The hotter an object is the more thermal radiation is emits.

Dark, matt surfaces absorb radiation better than light, shiny surfaces.

Dark, matt surfaces emit more radiation than light, shiny surfaces.

We see black because it absorbs all the radiation and reflects none back into our eyes.

A charged particle

They contain lots of free electrons that hold together the positive ions. They collide with each other and the ions. The electrons speed up when heated and collide with electrons in cooler parts of the metal passing on the (kinetic) energy.

Atoms shake and vibrate (more when heated) transferring energy. This is much less effective than free electrons.

The hot air above the heat source rises in temperature, and expands becoming less dense. Therefore it rises while more dense, cooler air take its place.

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The water is heat up in the boiler. As water is heated it expanse, becomes less dense, and rises. This rise up a tube into the "Hot Tank". At the top of the hot tank is a tap. When turned out this tap will have hot water. If not the water cools down, contracts, becomes less dense and sink down to the bottom of the "Hot tank" then down a pipe in to the boiler to be heating again and therefore completing the cycle. 

On sunny day the ground heats up faster than the sea. The hot air above the ground expands, becomes less dense and rises, getting pushed up by cooler denser air from the sea.

1. It has a large surface area so it can lose heat quickly.

2. It is shiny white so the hot water doesn't lose all it's heat at the first radiator (leaving the rest of the house cold).

Because air is a good insulator. If you hold it above the flame it will light because heat rises.

Because the clouds reflect heat back to us.

So it absorbs as much energy as possible away from the fridge. The pipes on the back of the fridge get quite hot but inside it's cold.

1. Windows (10%)
2. Floors (15%)
3. Draughts (15%)
4. Roof (25%)
5. Walls (35%)

Pack back is the amount of time that insulation takes to pay for itself due to savings in bills.

We work it out by: Cost of fitting/Annual saving.

Architects can work out the heat lost from a building using U-values and a formulae.

Heat lost/Second =

U-Value x Area x Temperature difference

Temperature difference =

Temperature inside the house - Temperature outside the house.