Primary 3 Science · Investigation worksheet

Making Magnets: Investigation Practice

Name:Date:Marks: / 20

Section A · Multiple choice 8 marks

1. Look at Table 1. How many steel clips did the nail attract after 30 strokes?1 mark

Table 1: Steel nail stroked with the north pole of a magnet

Number of strokes	Steel clips attracted
10	2
20	5
30	7
40	10

(A) 5(B) 7(C) 10(D) 30

2. Which conclusion matches Table 1?1 mark

Table 1: Steel nail stroked with the north pole of a magnet

Number of strokes	Steel clips attracted
10	2
20	5
30	7
40	10

(A) The more strokes, the more clips attracted, so the stronger the magnet(B) The more strokes, the fewer clips attracted(C) The number of strokes does not change the number of clips(D) The nail is strongest after only 10 strokes

3. Meena wants to find out if the number of strokes changes how strong a steel nail becomes. Which variable must she keep the same?1 mark

(A) The number of strokes(B) The number of clips attracted(C) The strength of the nail after the test(D) The direction of the strokes

4. Zara wants to turn a steel needle into a magnet by the stroke method. Which is the correct way to stroke?1 mark

(A) Rub the magnet back and forth along the needle(B) Use the north pole going one way and the south pole coming back(C) Use the same pole and the same direction every time(D) Stroke the needle with a piece of wood

5. Look at Table 2. How many more clips did the electromagnet attract with 40 turns than with 10 turns?1 mark

Table 2: Iron nail, 1 battery, different turns of wire

Turns of wire	Steel clips attracted
10	3
20	6
30	9
40	12

(A) 3(B) 9(C) 6(D) 12

6. Look at Table 3. Which two set-ups give a fair test to find out if the number of turns of wire changes the strength of the electromagnet?1 mark

Table 3: Four electromagnet set-ups (all use the same type of iron nail and the same clips)

Set-up	Turns of wire	Batteries
P	10	1
Q	20	1
R	20	2
S	30	3

(A) P and Q(B) P and R(C) Q and S(D) R and S

7. After lifting some clips, Mei finds that the wires and nail feel warm. What should she do first?1 mark

(A) Add another battery(B) Wind more wire onto the nail(C) Touch the bare wires to check how hot they are(D) Disconnect the wire from the battery

8. A scrapyard crane uses an electromagnet to lift old cars. Why is an electromagnet better than an ordinary magnet for this job?1 mark

(A) It attracts wood and plastic too(B) It does not need electricity(C) Its magnetism can be switched off to drop the car(D) Its poles repel iron so the car floats

Section B · Show what you know 12 marks

9. Look at Table 5. Name the variable that Mei changed and the variable that she measured.2 marks

Table 5: Iron nail with 20 turns of wire

Number of batteries	Steel clips attracted
1	6
2	10
3	14

10. Dan says, "More strokes make a weaker magnet." Look at Table 4. Is Dan's test a fair test? Explain.2 marks

Table 4: Dan's results

Test	Number of strokes	How the nail was stroked	Clips attracted
1	10	same pole, same direction every time	3
2	30	back and forth, using both ends of the magnet	1

11. Mei tried 20 turns of wire three times, as in Table 6. Why did she repeat the test? What do her results tell her?2 marks

Table 6: Iron nail, 20 turns of wire, 1 battery

Try	Clips attracted
1	6
2	7
3	6

12. Use Table 2 to predict the number of clips for 50 turns of wire. Give a reason for your prediction.2 marks

Table 2: Iron nail, 1 battery, different turns of wire

Turns of wire	Steel clips attracted
10	3
20	6
30	9
40	12

13. Ali made the electromagnet shown. It attracts only 1 clip. Suggest two ways to make it stronger.2 marks

14. Look at the bar chart. Which two set-ups show the effect of the number of batteries? What does the chart show about batteries?2 marks

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