Physics · Unit 6

Energy and Its Forms

The power to make things happen

Energy is the quantity that stays constant while everything else changes, and that conservation is why it is worth tracking at all.

The unit covers what energy is, its main forms, kinetic and stored energy, and transfer between forms - which is what every physical process ultimately is.

This unit breaks down into 20 short steps and 119 questions, starting at difficulty 1 and building to 2. Below you can see exactly what it covers, how the path is structured, and worked examples with explanations.

Steps: 20
Questions: 119
Difficulty: 1-2

What this unit covers

Stored Energy
Kinetic Energy
Forms of Energy
What Is Energy
Energy Transfer

Where this fits

Pairs with Work, Energy and Power, which puts numbers on it.

Where people slip

Energy is a property of a system, not a substance inside it. Asking where the energy went is really asking which store it moved to.

How the unit is structured

Energy and Its Forms runs as 20 short steps that unlock in order. 15 are practice rounds and 5 are challenge rounds that pull together everything before them. Questions start at difficulty 1 and climb to 2 as you progress.

Step 1 · easierStep 20 · harder

Challenge rounds

Example questions

30 real questions from this unit, with the answer and the reason behind it, grouped by what they practise. There are 119 in the unit altogether.

Energy Transfer

Build the sentenceLevel 1
1. Put the words in order to finish this rule about energy.
Answer: Energy is never lost it just changes form
Energy is never really lost - it just changes from one form into another.
Fact or fibLevel 1
2. When energy changes form, some of it usually turns into heat.
Answer: True
Whenever energy changes form, some is often given off as heat, like a phone getting warm while you use it.
Guess the numberLevel 1
3. In an old-style light bulb, out of every 10 units of energy going in, only about how many turn into light?
Answer: 1 units
Old light bulbs waste most of their energy as heat, turning only about 1 unit out of every 10 into light.
Multiple choiceLevel 1
4. When you rub your hands together quickly, movement energy changes mostly into what?
- Heat energycorrect
- Sound energy
- Light energy
- Cold energy
Rubbing your hands turns movement (kinetic) energy into heat energy, which is why they feel warm.
Put in orderLevel 1
5. Put the energy changes in a torch in the right order.
Answer: Chemical energy in the battery -> Electrical energy in the wires -> Light energy from the bulb
In a torch, chemical energy in the battery becomes electrical energy in the wires, then light energy from the bulb.
Match the pairsLevel 2
6. Match each device to the useful form of energy it is designed to give out.
Answer: A lamp = light energy; A kettle = thermal energy; A loudspeaker = sound energy; An electric motor = kinetic energy
Devices convert electrical energy into the useful form we want, such as light, heat, sound or motion.

Forms of Energy

Choose all that applyLevel 1
7. Which of these are forms of energy? Pick all that apply.
- Lightcorrect
- Soundcorrect
- Electricalcorrect
- A brick
Light, sound, and electrical are all forms of energy, but a brick is just an object.
Fill the blankLevel 1
8. The energy that we hear with our ears is called ____ energy.
- soundcorrect
- light
- heat
- cold
Sound energy travels to our ears and lets us hear things like music and voices.
Match the pairsLevel 1
9. Match each thing to the form of energy it gives out.
Answer: A lamp = Light; A heater = Heat; A speaker = Sound; A wall socket = Electrical
Different objects give out different forms of energy, such as light, heat, sound, or electrical energy.
Multiple choiceLevel 1
10. Which of these is a form of energy?
- Soundcorrect
- A wooden chair
- A plastic cup
- A paper bag
Sound is a form of energy; the chair, cup, and bag are just objects, not forms of energy.
Build the sentenceLevel 2
11. Build a true sentence about sound.
Answer: sound is a form of energy
Sound is one of the many forms that energy can take.
Fact or fibLevel 2
12. As countries try to cut carbon emissions, the share of electricity in the national energy mix coming from renewables such as wind and solar is expected to grow in the future.
Answer: True
To reduce greenhouse gases, the energy mix is shifting away from fossil fuels toward renewable resources.

Kinetic Energy

Choose all that applyLevel 1
13. Which of these have kinetic energy? Pick all that are moving.
- A spinning wheelcorrect
- A flowing rivercorrect
- A running childcorrect
- A statue standing still
A spinning wheel, flowing river, and running child are all moving, so they have kinetic energy; a still statue does not.
Fact or fibLevel 1
14. The faster something moves, the more kinetic energy it has.
Answer: True
Speeding up gives an object more kinetic energy, which is why a fast ball hits harder than a slow one.
Fill the blankLevel 1
15. Any object that is moving has ____ energy.
- kineticcorrect
- sleepy
- frozen
- empty
Kinetic energy is the energy of motion, so anything moving has kinetic energy.
Multiple choiceLevel 1
16. Kinetic energy is the energy of what?
- Moving thingscorrect
- Sleeping things
- Cold things
- Empty things
Kinetic energy is the energy that moving things have - anything that moves has kinetic energy.
Odd one outLevel 1
17. Which of these has NO kinetic energy?
- A book resting on a shelfcorrect
- A rolling ball
- A running dog
- A flying bird
A book sitting still has no kinetic energy, while a rolling ball, running dog, and flying bird are all moving.
Guess the numberLevel 2
18. A 1000 kg car travels at 10 m/s. Using kinetic energy = one half x mass x speed squared, what is its kinetic energy?
Answer: 50000 J
KE = 0.5 x 1000 x 10 x 10 = 50000 J.

Stored Energy

Fact or fibLevel 1
19. A ball at the top of a hill has more stored energy than the same ball at the bottom.
Answer: True
The higher something is, the more stored energy it has because of its height.
Fill the blankLevel 1
20. Energy that is stored up ready to be used is called ____ energy.
- potentialcorrect
- moving
- missing
- tiny
Potential energy is stored energy, like the energy in a stretched spring waiting to be released.
Match the pairsLevel 1
21. Match each object to where its stored energy comes from.
Answer: A battery = Chemicals inside; A rock high on a hill = Its height; A stretched bow = Being stretched; A wound-up spring = Being twisted
Stored energy can come from chemicals, height, stretching, or twisting, depending on the object.
Multiple choiceLevel 1
22. What do we call energy that is stored and waiting to be used?
- Potential energycorrect
- Kinetic energy
- Loud energy
- Empty energy
Stored energy that is ready to be used is called potential energy.
Odd one outLevel 1
23. Which one is NOT storing energy ready to be released?
- A ball already rolling on flat groundcorrect
- A stretched catapult
- A raised hammer
- A full battery
A ball already rolling is using kinetic energy, while a catapult, raised hammer, and battery are all storing energy.
Guess the numberLevel 2
24. A 2 kg book is lifted 5 m onto a shelf. Using gravitational potential energy = mass x g x height with g = 10 m/s squared, how much energy does it gain?
Answer: 100 J
GPE = 2 x 10 x 5 = 100 J.

What Is Energy

Build the sentenceLevel 1
25. Put the words in order to finish the sentence.
Answer: Energy makes things move and change
Energy is what makes things move and change.
Fill the blankLevel 1
26. Energy is the ability to do ____.
- workcorrect
- nothing
- sleep
- colour
Scientists say energy is the ability to do work, which means making things move or change.
Multiple choiceLevel 1
27. What does energy let things do?
- Move, work and change
- Turn invisible
- Become heavier
- Stop existing
Energy is what lets things move, do work, and change - without it nothing would happen.
Odd one outLevel 1
28. Which one is NOT a source of energy?
- A plain grey rockcorrect
- The Sun
- A battery
- Food
The Sun, batteries, and food all give us energy, but a plain rock just sits there without giving any.
Choose all that applyLevel 2
29. Which of these are common ways that useful energy is wasted (dissipated) by everyday machines? Select all that apply.
- Heat transferred to the surroundingscorrect
- Sound produced by moving partscorrect
- Useful light from a reading lamp
- Energy still stored in fuel before it is used
Energy is usually wasted as heat and sound to the surroundings; useful light and stored fuel energy are not wasted.
Guess the numberLevel 2
30. One kilojoule (kJ) is a larger unit of energy. How many joules are there in 1 kilojoule?
Answer: 1000 J
The prefix kilo means one thousand, so 1 kJ equals 1000 J.

Where these questions come from. Each unit starts as a plan of the concepts it should cover and the difficulty it should span. Questions are written against that plan with AI assistance, then checked by a validator that rejects anything without a single defensible answer, an explanation, or plausible wrong options. How we write questions sets out the whole process, and corrections are fixed in the bank and reach the site and the app the same day.

How you practise

This unit mixes 17 different question formats, so you are recalling and applying rather than recognising the same layout every time.

Build the sentence
Choose all that apply
Fact or fib
Fill the blank
Guess the number
Listen and choose
Match the pairs
Multiple choice
Odd one out
Picture question
Put in order
Sequence recall
Sort into groups
Spell it
Tap the pairs
True or false
Type the answer

Practise Energy and Its Forms

119 questions across 20 steps. Start with step one and crawl at your own pace.

Play this unit

Read about Energy and Its Forms

Explainers from our blog on what this unit covers. Each one ends with real questions from the bank.

How Springs Store and Release EnergyA spring changes shape when a force stretches or compresses it. Within its elastic range, the extension follows a simple pattern and energy is stored for later release.August 5, 2026 · 5 min read

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