P1.1

Question 1

What type of radiation doesn’t require particles?

Answer 1

Infrared

Question 2

What can infrared radiation be detected with?

Answer 2

A thermogram

Question 3

What objects are best at absorbing and emitting?

Answer 3

Dull, Matt objects

Question 4

Why are metals good conductors of heat?

Answer 4

The atoms are arranged in neat rows and columns and they have delocalised electrons that can move freely

Question 5

Why are plastic, wood and polystyrene bad conductors of heat?

Answer 5

Their atoms are not arranged neatly and there are no delocalised electrons

Question 6

What does convection happen in?

Answer 6

Liquids and gases

Question 7

What do insulators do?

Answer 7

Keep warmth from leaving and entering

Question 8

Describe the process of convection

Answer 8

The particles are heated and gain energy, then they separate and become less dense and rise. When they rise they get further away from the heat so cool down, lose energy, become more dense and fall back down again

Question 9

Why do solids, liquids and gases expand when they’re heated?

Answer 9

The particles gain more energy and vibrate more, causing them to take up more space

Question 10

What is the kinetic theory?

Answer 10

Particles in solids, liquids and gases have different amounts of energy

Question 11

What can you do to increase heat transfer?

Answer 11

Increase surface area
Change surface that object is on
Use a metal surface as its a good conductor

Question 12

Cooling fins are used at the back of fridges, car radiators etc. Why do they have such a large surface area?

Answer 12

To stop them getting hot

Question 13

What adaptations do animals living in hot climates have?

Answer 13

Large ears as they have a large surface area and keeps them cool

Question 14

How are animals adapted to live in cold climates?

Answer 14

Having a large volume and small surface area

Small ears

Question 15

What does U-Values measure?

Answer 15

The rate of heat transfer through a material

Question 16

What does high U-Value mean?

Answer 16

Lots of heat energy is transferred

Question 17

What does low U-Value mean?

Answer 17

Little heat energy is transferred (ideal for houses)

Question 18

What is specific heat capacity?

Answer 18

The amount of energy required to raise 1kg of a substance by 1 degrees Celsius

Question 19

How does liquid evaporate?

Answer 19

The top layer of particles absorb heat energy from the surroundings which causes them to vibrate more. This allows them to break the forces of attraction and escape with their heat as gas particles. This gradual change of state makes the liquid cool down as small amounts of heat escape

Question 20

What are the properties of a solid?

Answer 20

Low particle energy
Fixed volume
Fixed shape

Question 21

What are the properties of a liquid?

Answer 21

Medium particle energy
Fixed volume
Takes the shape of its container

Question 22

What are the properties of a gas?

Answer 22

High particle energy
Far apart
Fill the available space

Question 23

What’s the definition of U-value?

Answer 23

How good a material is at insulating

Question 24

Why would you want an object to emit radiation?

Answer 24

To give maximum rate of energy transfer to surroundings

Question 25

What is meant by efficiency?

Answer 25

The amount of useful energy given out

Question 26

Why is trapped air a good insulator?

Answer 26

There are no convection currents

Question 27

How do thermometers work?

Answer 27

Temperature increase causes the particles to gain energy and move more, therefore the liquid expands and rises up the thermometer

Question 28

How can a thermogram detect injuries in the body?

Answer 28

~ It will show the area as red

~ The area will be red due to it being inflamed and more blood surrounding it, which makes it hotter

Question 29

Why do dull/matt surfaces absorb and emit more heat than shiny surfaces?

Answer 29

Because lots of infrared radiation is reflected by shiny, light surfaces

Question 30

What type of surface absorbs and emits the most heat fastest?

Answer 30

Dull, black surfaces

Question 31

How can the rate of heat transfer be increased?

Answer 31

A greater difference in temperature between the object and its surroundings

Question 32

How can the rate of heat transfer be decreased?

Answer 32

The use of insulation

Question 33

What is conduction?

Answer 33

The transfer of heat energy without the substance moving

Question 34

Why does steel require more heat for conduction to take place?

Answer 34

Because it’s particles aren’t as compact, so more energy is needed for the particles to hit each other and pass on the energy

Question 35

What is condensation?

Answer 35

When warm gases come into contact with a cold surface, which cools the particles so that they no longer have enough energy to move as gases

Question 36

What is insulation?

Answer 36

Covering or separating using a material. It reduces or prevents the transfer of heat, electricity and sound

Question 37

What is convection?

Answer 37

The transfer of heat energy through movement. It occurs in liquids and gases and creates convection currents

Question 38

Why does condensation cause a temperature increase?

Answer 38

Because particles in a gas have more energy than in a liquid. So, when a gas condensed to form a liquid, this energy is released

Question 39

How does a vacuum flask reduce heat transfer?

Answer 39

~ Made from plastic, which is a poor insulator

Question 40

Why is it a good idea to have curtains in your house?

Answer 40

To stop heat loss through convection