Magnetism – Session 10 , 11, 12
Session 10 on 4th Feburary 2012
The learning goal for this session was –
- Magnetic substances can be magnetized using electricity.
- Factors that impact the strength of an electromagnet.
The class started with a recap of how we magnetized an iron nail by striking it against a magnet. The students were then asked to explain their experience and they all said that it took a long time to magnetize and the iron nail did not stay as a magnet for long.
It was time to introduce another method. We did the same things – took an iron nail, verified that it was not already magnetized. Then, took a battery/cell and wound a copper wire around the iron nail, connected it to both the ends of the battery. As I was holding the battery and the nail, I asked the students to say what I did. This was just to keep them engaged in the class and also to let a few minutes pass by so that the nail would get magnetized. By the time they finished answering, I took the iron nail near a paper clip and the clip got attracted. The students were so excited as the nail got magnetized so fast and it was able to attract many paper clips and also was retaining its strength for long.
Then we compared the 2 methods of magnetizing the nail – the similarities and differences.
We then started looking at the various factors that would affect the strength of the electromagnet. Used lesser number of windings and more number of windings in the nails to show the difference. Though there are other factors like – the power of the battery, the thickness of the copper wire, we did not look at them in this class.
Now that we completed most of what I planned in magnetism, I wanted to spend the rest of the sessions in exposing them to different questions on magnets. The intention was to expose them to different questions and to find how much they have understood. This was done in session 11.
After spending session 11 on multiple choice questions, i realized that having them describe what they knew about magnets would be an interesting way to identify what they have learnt. The class was free to express what they knew in writing/drawings. They came up with some great stuff which I will scan and post soon.
learningtoteachscience 
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