Year 7 Science · Unit 3 · Lesson 13
Foundation Worksheet
Learning Goals
Match each term to its meaning
Write the letter of the correct meaning next to each term. Each letter is used once.
| Term | Letter | Meaning |
|---|---|---|
| Work | A. The rule that energy is never created or destroyed, only moved or changed | |
| Kinetic energy | B. Stored energy, in a stretched band, a squashed spring or a lifted object | |
| Potential energy | C. A force between rubbing surfaces that turns movement energy into heat | |
| Friction | D. The energy a moving object has | |
| Conservation of energy | E. What a force does when it makes an object move and transfers energy to it |
True or false? Fix the false ones
Circle T or F. If a statement is false, correct it on the line.
1. Holding a heavy box perfectly still above your head does work on the box.
Correct it:
2. A stretched elastic band stores elastic potential energy.
Correct it:
3. The higher you lift a school bag, the more gravitational potential energy it stores.
Correct it:
4. When a rolling ball slows down and stops, its energy disappears.
Correct it:
5. Only non-contact forces can transfer energy to an object.
Correct it:
1. A student says: “When I kick a still ball and it speeds away, no energy moved anywhere.” Is the student correct? Explain, using the word work.
Sort it: which kind of energy?
Write each item in the box for the kind of energy it mainly has. The boxes do not hold the same number of items.
Elastic potential energy
Gravitational potential energy
Kinetic (movement) energy
Trace the energy
For each situation, write where the energy starts and where it ends up. Choose from: chemical energy in muscles, elastic potential energy, gravitational potential energy, kinetic (movement) energy, heat and sound.
| Situation | Energy starts as | Energy ends up as |
|---|---|---|
| An archer lets go of a drawn-back bow and the arrow flies off. | ||
| A mango falls from a branch towards the ground. | ||
| A sprinter skids to a stop, and the soles of her shoes get warm. |
Read the data: warming your hands
Scenario: a cold morning at camp
A class measured the temperature of their palms with a skin thermometer, then rubbed their hands together hard for different times. Table 1 shows how much the palm temperature went up.
| Rubbing time (s) | Rise in temperature (°C) |
|---|---|
| 0 | 0 |
| 10 | 1.5 |
| 20 | 3.0 |
| 30 | 4.0 |
| 40 | 4.5 |
Source: sample class results, class average.
2. Describe the pattern in Table 1. Quote two values from the table.
3. Name the force that warms the hands. Then explain where the heat energy came from, starting with the student’s muscles.
4. A child climbs the ladder of a playground slide, slides down, and stops at the bottom with warm legs. Trace the energy from start to finish. Use the words force, energy and conserved.
Match each term to its meaning
Work → E; Kinetic energy → D; Potential energy → B; Friction → C; Conservation of energy → A.
True or false
1. False: no movement, so no work. 2. True. 3. True. 4. False: friction turns it into heat and sound. 5. False: contact forces do too, e.g. a kick.
Question 1
No (1). The push moves the ball, so the foot does work: energy passes from the muscles to the ball as kinetic energy (1). [2 marks]
Sort it: which kind of energy?
Elastic: the bow; the pen spring; the trampoline mat. Gravitational: the book on a high shelf; the rock at the top of a cliff. Kinetic: the bowling ball; the bike.
Trace the energy
1 mark per row. Arrow: elastic potential → kinetic. Mango: gravitational potential → kinetic. Sprinter: kinetic → heat and sound, by friction. [3 marks]
Question 2
The longer the rubbing, the bigger the rise (1), with two values quoted, e.g. 1.5 °C at 10 s, 4.5 °C at 40 s (1). [2 marks]
Question 3
Friction (1). Chemical energy in the muscles gives the hands kinetic energy (1). Friction between the palms turns it into heat (1). [3 marks]
Question 4
Marking guide, 1 mark each: chemical energy in the muscles; climbing against gravity stores gravitational potential energy; going down, gravity does work and it becomes kinetic energy; friction turns kinetic energy into heat (warm legs) and sound, so the child stops; energy is conserved, none is destroyed. [5 marks]
Model answer: Chemical energy in her muscles lifts her against gravity, storing gravitational potential energy. Sliding down, the force of gravity does work, giving kinetic energy. Friction turns that into heat and sound, so her legs warm and she stops. Energy is conserved.
Common error: saying energy “disappears” when something stops.