Energy und Heat Transfer

Question 1

Energy is…

Answer 1

The ability to do work.

Question 2

What are the 8 energy stores?

Answer 2

Kinetic, magnetic, nuclear, gravitational, elastic, chemical, electrostatic and thermal.

Question 3

What are the 4 kinds of energy pathways?

Answer 3

Heating, radiation, electrical and mechanical.

Question 4

What is the law of conservation of energy?

Answer 4

Total energy before transfer = total energy after transfer.

Question 5

What is the unit for energy?

Answer 5

Joules.

Question 6

What is the most commonly used unit for energy in food?

Answer 6

Calories.

Question 7

What are fossil fuels?

Answer 7

Fossil fuels are non-renewable energy resources made of fossils of plants and animals.

Question 8

What are the three types of fossil fuels?

Answer 8

Coal, oil and gas.

Question 9

How is coal formed?

Answer 9

Some dead plants millions of years ago fell into swamps. The mud and water stopped the plants decaying and they slowly get covered with sediment. The heat and pressure turn the plants into coal.

Question 10

What are the main kinds of renewable energy?

Answer 10

Solar (thermal or photovoltaic), geothermal, biomass, tidal, wind, hydroelectric and waves.

Question 11

What are the 5 questions you need to ask to see if an energy resource’s advantages?

Answer 11

Is it reliable?
Does it release air pollution?
Does it need a fuel?
Does it have any effects on local habitats/ecosystems?
Does it need a special location?

Question 12

What is heat transfer?

Answer 12

It is when heat from a hot object gets transferred to a colder object.

Question 13

How is temperature determined?

Answer 13

It is the average of the kinetic energy store in the particles of an object.

Question 14

What are the two things that determine the temperature?

Answer 14

The size and heat of an object.

Question 15

What are the 3 types of heat transfer?

Answer 15

Conduction, convection and radiation.

Question 16

How is heat transferred in non-metal solids?

Answer 16

Atoms near the heat source begin to vibrate. These vibrations make adjacent atoms vibrate.

Question 17

Why are metals good conductors?

Answer 17

Because they have many free electrons that carry energy from high energy atoms to low energy ones.

Question 18

Density=

Answer 18

Mass/Volume

Question 19

A increase in volume=

Answer 19

A decrease in density.

Question 20

When a substance becomes less dense, do the atoms get larger?

Answer 20

No, the gaps between atoms get bigger.

Question 21

How are convection currents formed?

Answer 21

When a heat source is placed in an area filled with fluids.

Question 22

How do convection currents work?

Answer 22

Air near a heat source heats up and becomes less dense. The hot air rises. To fill in the vacuum near the heat source, the colder, more dense air which is far from the heat source sinks to near the heat source. The cold air gets heated up and the cycle repeats, causing a convection current.

Question 23

What is unique about radiation?

Answer 23

It travels via waves, not particle.

Question 24

What kind of material is the best radiator?

Answer 24

Matt black.