Heating And Cooling

Question 1

Explain radiation

Answer 1

Infrared radiation transfers energy by waves, in a similar way to light. It does not need a medium to travel through and can pass through transparent substances like air or glass. Infrared radiation can also be focused

Question 2

Explain conduction

Answer 2

Conduction transfers energy by heat. When a solid gains thermal energy the particles vibrate more. This means they collide with each other, passing the energy throughout the solid. This happens is solids from hotter to colder areas

Question 3

Explain convection

Answer 3

Energy is transferred through fluids by convection. When part of a fluid is heated up it expands and becomes more dense that the slugs around it. Then if floats upwards through the remaining fluid.

Question 4

How are convection currents formed ?

Answer 4

1. Heating a liquid or gas makes the particles move faster and spread out
2. The hot liquid/gas becomes less dense and raises
3. As it moves away from the heat source, it cools down, becomes denser and sinks
4. This creates a convection current

Question 5

Give an example of a convection current

Answer 5

Radiators in a rom : hot air raises and cold air sinks, spreading hot

Question 6

How can we control energy transfers ?

Answer 6

In cold climates, people can keep their houses warm by burning fuels for heating. Insulation can help to keep the warmth inside the houses. For example, brick, wood and other building materials are good thermal insulators

Question 7

What happens to the particles when they are heated ?

Answer 7

The particles move faster and they spread out.

Question 8

What happens to the particles when they are cooled ?

Answer 8

The particles slow down and come closer together. This makes the material contract

Question 9

How do our bodies use food to get energy ?

Answer 9

Food has chemical energy ( carbohydrates ) so therefore when we eat it we get the energy

Question 10

What is the difference between temperature and thermal energy ? .

Answer 10

The particles that everything is made from are always moving, The energy stored in the movement of particles is called thermal energy. It is measured in joules. Temperature is how hot or cold and object is. It is measured in degrees Celsius.

Question 11

What does the amount of internal energy stores on something depend on ?