4b P1 energy 4c LM

Question 1

what are the energy stores?

Answer 1

chemical, kinetic, gravitational, elastic, thermal, magnetic, electrostatic and nuclear

Question 2

what are the energy transfers?

Answer 2

mechanically, electrically, by heating, by radiation (light and sound)

Question 3

what is the principle of conservation of energy?

Answer 3

Energy cannot be created or destroyed, it can only be transferred from one store to another

Question 4

how does thermal energy transfer?

Answer 4

conduction, convection, radiation

Question 5

what is conduction?

Answer 5

• heat loss to surfaces in contact with the object

- main method of thermal energy transfer in solids

Question 6

what is convection?

Answer 6

the main way heat travels through liquids and gases

Question 7

what is radiation?

Answer 7

heat transfer by infrared

Question 8

what happens in conduction?

Answer 8

it will lose heat until both things reach a thermal equilibrium
for example a mug will cool down until it reaches room temperature

Question 9

what happens in convection?

Answer 9

• when a fluid is heated the molecules push each other apart making the fluid expand
• this makes the hot fluid less dense
• the fluid rises
• eventually it cools and sinks back down
• its called convection currents

Question 10

what happens in radiation?

Answer 10

every object emits a spectrum of thermal radiation, its heat transfer and the hotter the object the more infrared radiation it radiates

Question 11

what colour is best at emitting and absorbing thermal radiation?

Answer 11

black

Question 12

what colour is worst at emitting and absorbing thermal radiation?

Answer 12

white

Question 13

what is the only way can heat travel in a vacuum?

Answer 13

radiation

Question 14

where can convection happen?

Answer 14

liquids and gases only

Question 15

where can conduction happen?

Answer 15

metals and other solids