Energy Matters

Question 1

What is energy?

Answer 1

The ability to do work or cause change. Measured in Joules (J).

Question 2

What are the two main types of energy?

Answer 2

1. Kinetic energy
2. Potential energy

Question 3

What is the difference between potential and kinetic energy?

Answer 3

Kinetic: energy due to motion.
Potential: energy that is stored in an object.

Question 4

What are examples of potential energy?

Answer 4

Gravitational, chemical, elastic, nuclear.

Question 5

What is nuclear energy? (Potential)

Answer 5

energy stored in the nucleus of atoms. Released only from nuclear reactions. (breaking or making elements).
e.g The sun, stars (Fusion) Nuclear power plants, atomic bomb (Fission)

e.g. The sun, stars (Fusion), Nuclear power plants, atomic bomb (Fission)

Question 6

What is chemical potential energy?

Answer 6

potential energy stored within the chemical bonds of an object (gives energy to others).
e.g batteries for a torch

e.g. batteries for a torch.

Question 7

What is elastic potential energy?

Answer 7

potential energy due to compression or expansion of an elastic object.
e.g hair tie

e.g. hair tie.

Question 8

What is gravitational potential energy?

Answer 8

potential energy due to an objects position (up high). calculated by GPE = mass x height x gravity (10)

Question 9

What are examples of kinetic energy?

Answer 9

Sound, Light, Heat, Electrical.

Question 10

What is electrical energy?

Answer 10

energy caused by the movement of charges - transported through power line and converted into other useful forms of energy. e.g TVs, computers.

e.g. TVs, computers.

Question 11

What is sound energy?

Answer 11

the result when a force, either sound or pressure makes an object or substance vibrate.
e.g (Anything noisy), an airplane taking off, a balloon popping.

e.g. anything noisy, an airplane taking off, a balloon popping.

Question 12

What is light energy?

Answer 12

a kind of kinetic energy with the ability to make types of light visible to human eyes.
e.g (anything luminous), stars, light bulbs, lasers.

e.g. anything luminous, stars, light bulbs, lasers.

Question 13

What is heat energy?

Answer 13

determines how active atoms in an object are. a hot object is one whose atoms and molecules are excited and show rapid movement. a cooler object’s molecules and atoms will show less movement.
e.g warmth from the sun, baking in an oven.

e.g. warmth from the sun, baking in an oven.

Question 14

What is the formula for kinetic energy?

Answer 14

KE = 1/2mv^2, where m = mass (kg) and v = velocity/speed (m/s).
or
m=2KE / v^2
or
v= (square root of) 2KE / m

Question 15

What is the formula for gravitational potential energy?

Answer 15

GPE = mass x height x gravity (10).

Question 16

What is work?

Answer 16

The energy used in carrying out the task.

Question 17

What is the formula for work done?

Answer 17

W = force x distance.
or
F = W/d
or
d = W/F

Question 18

What is the Law of Energy Conservation?

Answer 18

Energy cannot be created or destroyed.

Question 19

What is energy transfer?

Answer 19

Type of energy moves from one object to another (does not change type).
e.g heat energy is transferred from the fire to the cat

e.g. heat energy is transferred from the fire to the cat.

Question 20

What is energy transformation?

Answer 20

energy converted from one type to another
e.g Soccer ball: GPE -> kinetic energy

e.g. Soccer ball: GPE -> kinetic energy.

Question 21

What is an energy flow diagram?

Answer 21

Diagram using arrows that shows the way energy is passed on or changed into other forms in a particular situation.
e.g
Fireworks: Potential chemical energy -> heat + light + sound
Light bulb: Electrical energy -> heat + light energy

e.g. Fireworks: Potential chemical energy -> heat + light + sound; Light bulb: Electrical energy -> heat + light energy.

Question 22

What is thermodynamics?

Answer 22

The study of how heat (thermal energy) can be transferred between objects or transformed into other forms of energy.

Question 23

What is a closed thermodynamic system?

Answer 23

No exchange of matter, may exchange energy (can only interact with what’s in the system).

Question 24

What is thermal equilibrium?

Answer 24

When the thermal energy of an object is the same as its surroundings. (thermal energy of a hot object with be transferred down the temp gradient to the cooler object)

Question 25

What is a temperature gradient?

Answer 25

When two objects are at different temperatures.

Question 26

What is conduction?

Answer 26

Energy is transferred by direct contact. e.g. Heat transfers into your hands as you hold a hot cup of coffee.

Question 27

What is convection?

Answer 27

Transfer of heat by the movement of a fluid (liquid or gas) between areas of different temperature. e.g. Heat transfer as the barista ‘steams’ cold milk to make hot cocoa.

Question 28

What is radiation?

Answer 28

Heat energy is transferred by infrared radiation which is in the form of waves of energy (does not require particles). e.g. reheating a cold cup of coffee in a microwave oven.

Question 29

What is the unit for energy?

Answer 29

Joules (J)

Question 30

What is the difference between a thermal conductor and an insulator?

Answer 30

Thermal conductors heat up quickly and transfer heat to surrounding areas. Thermal insulators prevent the transfer of thermal energy.