Energy (Yr_8)

Question 1

Describe light energy:

Answer 1

• essential to our lives
• sources: sun, light, globes, fires, some animals

Question 2

Describe heat energy:

Answer 2

• scientifically known as thermal energy
• can be generated by friction
• commonly generated by chemical reactions and electrical devices

Question 3

Describe electrical energy:

Answer 3

• sources: generators, power station, solar cells, batteries ad electrical devices
• can be used to power any sort of electrical device

Question 4

Describe potential energy:

Answer 4

• energy stored in an object waiting to be used
• can be the result of the change of shape, an object’s height and chemical reactions that change the chemical bomb

Question 5

Describe elastic potential energy:

Answer 5

• energy stored through the stretching and squashing of the physical shape
  the bigger the stretch, the more energy stored
• the bigger the stretch, the more energy stored

Question 6

Describe gravitational potential energy:

Answer 6

• an object in the air has the potential to fall due to gravitational pull
• the larger the mass and height, the higher the GPE

Question 7

Describe chemical potential energy:

Answer 7

• the energy stored within a chemical substance
• using chemical reactions to break the bonds holding the energy releases the energy

Question 8

Describe biomass energy:

Answer 8

• potential energy stored in plants and animals
• a type of chemical potential energy
• most common way to release energy is to burn the material

Question 9

Describe nuclear energy:

Answer 9

• involves the splitting or joining of the centre of atoms
• the amount of energy released from this reaction is much more than most chemical reactions

Question 10

Describe kinetic energy:

Answer 10

• scientific name for the energy of movement
• the speed and weight increase the kinetic energy
• the kinetic energy of a sudden stop is what hurts people

Question 11

Describe sound energy:

Answer 11

• sound is made when things vibrate
• it travels through vibrating particles

Question 12

List the rules for energy transformation:

Answer 12

1. the arrow points in the direction of the transformation
2. the energy input is written at the beginning of the arrow
3. the useful energy output is written at the tip of the arrow
4. there can be several energy transformations

Question 13

List some examples of transformation for heat:

Answer 13

Hairdryers: electrical top heat energy
Gas Ovens/stoves: chemical energy to heat energy
Waving Piece of Cardboard: chemical to kinetic to thermal energy

Question 14

List some examples of transformation for motion:

Answer 14

Riding a bicycle: chemical energy to kinetic energy or heat
car engines: chemical energy to kinetic energy and sound heat & electrical energy as by products

Question 15

List some examples of transformation for light:

Answer 15

• eyes merge the coloured light from the pixels to make the colours seen

Question 16

List some examples of transformation for sound:

Answer 16

Earphones: electrical to sound energy
All electrical devices follow the same pattern

Question 17

Describe what happens when transferring heat energy:

Answer 17

When substances are heated they expand to occupy more space as heating gives atoms more kinetic energy to move out faster and faster. Heat travels through materials in three ways, conduction, convection and radiation.

Question 18

Describe conduction

Answer 18

• the transfer of thermal energy between two objects in direct contact
• heat transfers from the hotter object ot the cooler objects
• hot atoms bump into the colder atoms transferring the thermal energy and heating up the object
• the atoms in the metal do not change positions

Question 19

Describe conductors & insulators:

Answer 19

• any material that allows thermal energy to flow easily through it is called a thermal conductor
• thermal insulators slow down the transfer of thermal energy because the arrangement of the atoms does not allow energy to flow easily

Question 20

Describe convection

Answer 20

• thermal energy may move by convection in liquids and gases
• convection currents are movement within a liquid or gas driven by difference in thermal energy
• the hotte less dense molecules rise, cool down, become more dense and sink down to be heated again, the cycle restarts

Question 21

Describe radiation

Answer 21

• a type of energy that includes visible light, ultraviolet light, radio waves, microwaves and infrared radiation
• the medium through which radiation travels through is not affected
• radiation may not always be absorbed, it may also be transmitted or reflected
• radiated energy that is absorbed gives the atoms in the substance more energy to vibrate which increases the substance’s thermal energy

Question 22

Define energy:

Answer 22

The capability of a system to do work or produce change. The unit for energy is joules.

Question 23

Define kinetic energy:

Answer 23

Kinetic energy is associated with an object’s motion

Question 24

Law of conservatives of energy:

Answer 24

The law of conservation of energy states that energy can neither be created nor destroyed.