Suggest an activity to prepare a magnetic compass by using an iron needle and a bar magnet.

Activity:

• Magnetise an iron needle using a bar magnet as described previously.
• Take a small piece of cork or foam and insert the magnetised needle through it. Take a cup filled with water and let the cork float in it.

• Make sure that the needle does not touch the water (see figure).
• Now, your compass is ready to work. Note the direction in which the needle points when the cork is floating. Rotate the cork in different directions.

• Note the direction in which the needle points when the cork begins to float again without rotating. We see that the needle always points in the same direction, when the cork floats without rotation.
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