Heat Energy

Question 1

Conduction

Answer 1

The transfer of energy from particle to particle, from the hotter end of the object to the cooler end of the object.

Question 2

Convection

Answer 2

The transfer of energy as particles move from place to place, from hotter part of liquid or gas to the colder part.

Question 3

Infrared radiation

Answer 3

As the particles vibrate they emit an invisible type of light called infrared radiation, as they do this they loose energy and move less so the temperature of the object falls.

Question 4

What happens the faster the particles vibrate in IR?

Answer 4

The more the particles vibrate the more IR they emit, so the hottest object emits the most IR.

Question 5

What happens when particles absorb IR?

Answer 5

It causes them to gain energy and move more so the temperature of the object rises.

Question 6

Hot objects

Answer 6

Emit more IR than they absorb, so overall they cool down.

Question 7

Cold objects

Answer 7

Absorb more IR than they emit, so overall they warm up.

Question 8

Dull, dark coloured surfaces

Answer 8

Good emitters and absorbers of IR.

Question 9

Shiny, light coloured surfaces

Answer 9

Poor emitters and absorbs of IR, they reflect it way instead, away from the object on the outside and back into the object on the inside.

Question 10

How does IR travel?

Answer 10

It does not require any particles in order to travel between particles and so can transfer heat energy through solids, liquids, gases and a vacuum of empty space.

Question 11

Expansion

Answer 11

The particles move further apart from each other, this causes the object overall to get bigger. Consequently the density is also reduced.

Question 12

What does heat energy do to the particles?

Answer 12

Heat energy cause the particles to move faster which, in turn, causes changes of state.

Question 13

What happens when 2 objects of different temperatures are placed in contact with each ther?

Answer 13

When 2 objects of different temperatures are placed in contact the hotter object will cool down and the colder one will heat up until they are both the same temperature.

Question 14

What happens to the kinetic energy in a particle when the objects gets hotter and colder?

Answer 14

When the hotter object gets colder it looses kinetic energy and when the colder object gets warmer it gains kinetic energy.

Question 15

What is heat energy measured in?

Answer 15

Joules (J).

Question 16

How much temperature changes depends on what?

Answer 16

The material it is made from (when the bonds are weak a small transfer of heat can result in a lot of extra vibration causing a large rise in temperature) and the number of particles in the object (if heat energy is shared between a large number of particles, the average increase in kinetic energy in each particle will be small).

Question 17

What are the different units of measure for temperature?

Answer 17

Degrees Celsius and Kelvin (k).

Question 18

What does the degrees celcuis define as 0 degrees and 100 degrees?

Answer 18

0 degrees is the point water freezes and 100 degrees is the point water boils.

Question 19

What is normal body temperature and room temperature?

Answer 19

Normal body temperature is usually 36 or 37 degrees and normal room temperature is usually 20 degrees

Question 20

What does the Kelvin scale define as 0K or absolute zero?

Answer 20

The point where the particles completely stop moving this is also known as -273 degrees.

Question 21

What do you do to convert degrees to kelvin?

Answer 21

Just add 273.

Question 22

What does temperature measure?

Answer 22

Temperature is a measure of the average kinetic energy of the particles in an object.

Question 23

How is temperature measured?

Answer 23

Temperature is measured using a thermometer, there are lots of different types.