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Natural sciences

Energy transfers and forces

Educator section

Memorandum

The more the knitting needle is stroked with the magnet, the more paper clips will be attracted by it. Learners can heat, drop or beat the knitting needle in order to destroy its magnetism.

Leaner section

Content

Activity 20: groupwork: to learn how to make a magnet [lo 2.4]

Each group will need: a bar magnet

a steel knitting needle

Prestik / wonder glue

10 paper clips

1. Use wonder glue to secure the knitting needle on the desk.

2. Slide the magnet along the knitting needle from end to end, making sure that you stroke the knitting needle in the same direction and use the same end of the magnet all the time. (Make a mark on the point of the knitting needle at which you lift the magnet while you are stroking it.)

3. Repeat the stroking movement 10 times and then check to see how many paper clips can be lifted with the needle.

___________________________

4. Repeat the stroking movement for another 10 times and see how many paper clips can be lifted now.

___________________________

5. What kind of pole do you have at the end where you have made the mark?_______

(Use the magnet with which you stroked the knitting needle for determining this and remember the law of magnetic poles, bearing in mind that the half of the magnet that is painted red is the north pole.)

6. Write down two things that you could do to destroy the magnetism of the knitting needle.

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

____________________________________________________________________

7. Follow your suggestions in point no. 6 to see if this does happen. YES / NO

8. Make a magnet of your own at home, but make use of electricity to create an electromagnetic magnet. Your teacher will explain how to do it. Check to see whether your magnet is able to attract magnetic materials when you bring it to class. This will serve as a measure to test the success of your work.

7. Uses of magnets:

Magnetic force is used daily to make our lives easier.

Assessment

Learning Outcome 2: The learner will know and be able to interpret and apply scientific, technological and environmental knowledge.

Assessment Standard 2.4: We know this when the learner application of knowledge: applies knowledge appropriately by connecting the learnt concept to a variation of the known situation.

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Source:  OpenStax, Natural sciences grade 7. OpenStax CNX. Sep 16, 2009 Download for free at http://cnx.org/content/col11077/1.1
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