Heat

Question 1

Describe the structure and of a solid

Answer 1

packed closely together, difficult to change, in rows and columns

Question 2

Describe the structure and of a liquid

Answer 2

remain relatively close to each other

Question 3

Describe the structure of a gas

Answer 3

molecules are not connected

Question 4

Describe the movement of a solid

Answer 4

confined to small vibrations

Question 5

Describe the movement of a liquid

Answer 5

molecules are free to move about

Question 6

Describe the movement of a gas

Answer 6

molecules moving in all directions, colliding with one another, and with the walls of their container,

Question 7

How does a solid turn into a liquid

Answer 7

melting

Question 8

How does a liquid turn into a gas

Answer 8

vaporising

Question 9

How does a gas turn into a liquid

Answer 9

condensation

Question 10

How does a liquid turn into a solid

Answer 10

freezing

Question 11

Name good thermal conductors

Answer 11

copper, tin, aluminium, iron

Question 12

Name good thermal insulators

Answer 12

feathers, polythene, wood

Question 13

What is conduction

Answer 13

the thermal transfer atoms between neighbouring atoms

Question 14

Describe the process of conduction

Answer 14

• atoms near heat source, heat up and vibrate more
• causes neighbouring atoms to vibrate MORE once they collide
• so the heat energy is transferred and spread through the material

Question 15

Why can conduction not take place in a vacuum

Answer 15

you need particles for conduction and there are no particles in a vacuum

Question 16

What surfaces are good absorbers of infrared radiation

Answer 16

dark, matt surfaces

Question 17

What surfaces are good emitters of infrared radiation

Answer 17

dark, matt surfaces

Question 18

What surfaces are poor absorbers of infrared radiation

Answer 18

light / shiny surfaces

Question 19

What surfaces are poor emitters of infrared radiation

Answer 19

light / shiny surfaces

Question 20

Why does convection not take place in solids

Answer 20

because solid particles are not free to move

Question 21

How is heat transferred due to radiation

Answer 21

through infrared waves

Question 22

Describe the process of convection

Answer 22

• a fluid or gas is heated
• the substance increases in temp and particles start to vibrate more
• the particles move further apart and reduces the density of the fluid
• the warmer fluid rises as it is less dense than the surrounding fluid

Question 23

What is radiation

Answer 23

things that are hot give out infrared radiation, we can’t see the radiation, but we can sense the heat

Question 24

What are the three methods of heat transfer (not including evaporation)

Answer 24

Conduction
Convection
Radiation

Question 25

What is meant by thermal radiation

Answer 25

infrared waves

Question 26

When a substance is heated during expansion, what happens to the atoms

Answer 26

the particles DO NOT expand - the space between them gets bigger so the overall substance expands

Question 27

How does heat energy move

Answer 27

from hot to cold

Question 28

What is the only method of heat transfer that can occur in a vacuum

Answer 28

radiation