Grade 7 science- Heat and Temperature topic 6

Question 1

Radiation

Answer 1

transfer of energy by electromagnetic rays, may occur in empty space. Examples: SUN, microwave, x-rays

Question 2

Convection

Answer 2

transfer of thermal energy from one place to another by the movement of fluids. Examples: hot air balloon

Question 3

Conduction

Answer 3

transfer of thermal energy that occurs in solids,liquids and gases when 2 different substances touch.
Examples: pot on stove.

Question 4

Radiant energy

Answer 4

energy is transferred by radiant energy or electromagnetic radiation

Question 5

EMR

Answer 5

Electromagnetic radiation

Question 6

Infrared radiation or heat

Answer 6

region of electromagnetic radiation spectrum- are longer than visible light but shorter then radio waves.

Question 7

Heat insulators (Insulators)

Answer 7

is when there are wrapped around an object and the transfer of thermal energy slows down to or from the surroundings.
Examples: Insulator: oven mitt
poor conductors are insulators a conductor is copper wire.

Question 8

fluids

Answer 8

a hot fluid can force its way through colder fluid. in convection the warmer fluid moves from place to place carrying thermal energy.

Question 9

Convection currents

Answer 9

as particles warm up they move farther apart each section of the warmed material is left with fewer particles them when it was cold so each section is a bit lighter
Example: when the water closest to the burner is warmed up it goes up and when the water gets cold it sinks being heated up again

Question 10

5 steps of energy transfer

Answer 10

1. Energy source: supplies energy to the rest of the system
2. Direction of energy: Always from high to low
3. Transformations:Energy does not keep the same form . it is converted from one form to another
4. Waste heat: All energy systems will loose heat because they are not 100% efficent
5. control system:It controls the amount of energy transfer

Question 11

Thermal conduction

Answer 11

the transfer of heat