Primary 3 Science · Answers and explanations
Magnets
Use this page to check the worksheet together. Talk about why each answer is right. Total: 16 marks.
Section A · Multiple choice 5 marks
1. Which of these is attracted to a magnet?
(A) A plastic ruler(B) An iron nail(C) A wooden block(D) A glass marble
Answer: (B) An iron nailIron is a magnetic material. Plastic, wood and glass are not.
2. Two magnets are placed with their north poles facing each other. What happens?
(A) They attract(B) They repel(C) Nothing happens(D) They become non-magnetic
Answer: (B) They repelLike poles (N and N) repel. Unlike poles (N and S) attract.
3. Where is a bar magnet the strongest?
(A) In the middle(B) At the poles(C) Everywhere equally(D) Nowhere
Answer: (B) At the polesThe pull of a bar magnet is strongest at its two ends, called poles.
4. A freely hanging bar magnet comes to rest. Its north-seeking pole points towards the…
(A) East(B) Earth's north(C) The ground(D) The Sun
Answer: (B) Earth's northA magnet can be used as a compass because it lines up with the Earth's magnetic field.
5. Which is a use of magnets?
(A) Keeping a fridge door closed(B) Making water cold(C) Making food sweet(D) Making a room bright
Answer: (A) Keeping a fridge door closedFridge doors have magnetic strips that hold the door shut.
Section B · Fill in the blanks 5 marks
Word bank: poles · attract · repel · magnetic · non-magnetic
6. The two ends of a magnet are called its .
Answer: polesEvery magnet has a north pole and a south pole.
7. A north pole and a south pole each other.
Answer: attractUnlike poles attract.
8. Two south poles each other.
Answer: repelLike poles repel.
9. Iron is a material.
Answer: magneticMagnetic materials are attracted to magnets.
10. Paper is a material.
Answer: non-magneticPaper is not attracted to a magnet.
Section C · Short answers 6 marks (2 each)
11. Ali has a plastic box with some paper clips inside. How can he pick up all the paper clips without opening the box?
Model answer: He can hold a magnet outside the box and move it. The magnet pulls on the paper clips through the plastic.Magnetic force acts through non-magnetic materials such as plastic.
12. Name two materials that are magnetic.
Model answer: Iron and steel. (Also accept nickel or cobalt.)Metals do not all behave the same way. Only some metals are magnetic.
13. How can you tell which pole of a magnet is its north pole, using another magnet whose poles are labelled?
Model answer: Bring the labelled north pole near each end. The end it pushes away (repels) is the north pole.Like poles repel. Attraction alone can mislead, because a magnetic material is attracted to either pole.
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