Year 7 Science · Unit 3 · Lesson 14
Foundation Worksheet
Learning Goals
Fill the gap
Choose the correct word from the word bank. Each word is used at most once. Two words are not needed: cross them out.
Every magnet has two poles, a pole and a south pole. Like poles each other, which means they push apart. Unlike poles each other, which means they pull together. A magnetic material such as is attracted to a magnet, but wood and copper are not. As an object moves further from a magnet, the magnetic force gets . A material like is not magnetic, so a magnet does not attract it.
True or false? Fix the false ones
Circle T or F. If a statement is false, correct it on the line.
1. Two south poles pull together.
Correct it:
2. Poles always come in pairs, so every magnet has two.
Correct it:
3. Magnetism is a non-contact force: it can act across a gap.
Correct it:
4. The pull of a magnet is the same at every distance.
Correct it:
5. A compass needle is a small magnet that lines up with Earth’s magnetic field.
Correct it:
1. State the rule of polarity. Use the words like poles and unlike poles.
Sort it: will a magnet pick it up?
Write each object in the correct box. The boxes do not hold the same number of items.
Attracted to a magnet
Not attracted to a magnet
2. Sketch a pair of magnets lined up so that they repel. Write N or S at every end, and add an arrow showing the direction each one moves.
Read the data: a chain of paper clips
Scenario: Sam’s paper clip chain
Sam holds a bar magnet with plastic spacers stuck under it, so there is a gap between the magnet and the first steel paper clip. Each spacer is 2 mm thick. He counts how many clips hang in a chain below the magnet. He uses the same magnet and the same clips every time.
| Gap (mm) | Clips held |
|---|---|
| 0 | 7 |
| 2 | 5 |
| 4 | 3 |
| 6 | 2 |
| 8 | 1 |
| 10 | 0 |
Source: sample class results.
3. Describe the pattern in Table 1. What does it tell you about the magnetic force?
4. Sam used plastic spacers. Explain why plastic is a good choice, and why steel washers would not work as spacers.
5. Jack says: “A magnet will stick to anything made of metal.” Explain whether Jack is right. Then describe how you could use a magnet to test an unknown object, and what the result would tell you.
Fill the gap
north; repel; attract; iron; weaker; plastic. Not used: south, stronger.
True or false
1. False: two south poles are like poles, so they repel. 2. True. 3. True. 4. False: the pull weakens with distance. 5. True.
Question 1
Like poles repel (N and N, or S and S push apart) (1). Unlike poles attract (N and S pull together) (1). [2 marks]
Sort it: will a magnet pick it up?
Attracted: iron nail; steel paper clip; steel food tin. Not attracted: aluminium can; copper wire; plastic ruler; wooden pencil; glass marble.
Question 2
Two magnets with like poles facing (N next to N, or S next to S), all four poles labelled (1). Arrows show the magnets pushed away from each other (1). [2 marks]
Question 3
The bigger the gap, the fewer clips are held, from 7 with no gap to 0 at 10 mm (1). The magnetic force gets weaker as the distance increases (1). [2 marks]
Question 4
Plastic is not magnetic, so it only adds distance (1). Steel washers are magnetic: they would stick to the magnet and pull on clips themselves, so the test would not measure distance alone (1). [2 marks]
Question 5
Marking guide, 1 mark each: Jack is wrong; only iron, nickel and cobalt are magnetic; steel is attracted as it is mostly iron; copper and aluminium are metals that are not; test: touch it with a magnet, and if attracted it contains iron, nickel or cobalt, if not it may still be a metal. [5 marks]
Model answer: Jack is wrong. Only iron, nickel, cobalt and their alloys, such as steel (mostly iron), are magnetic. Copper and aluminium are metals that a magnet does not attract. Touch the object with a magnet: if pulled, it contains iron, nickel or cobalt; if not, it may still be a metal.
Common error: thinking all metals are magnetic.