suggest any one reason why the use of a compass is preferable to the use of iron fillings??
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Answer:
Iron filings are very small pieces of iron that look like a light powder. They are very often used in science demonstrations to show the direction of a magnetic field.
By the way is that Hande Ercel in your dp.
Answer:
Q & A: magnetic iron filings
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Most recent answer: 10/22/2007
Q:
Why do iron filings line up in a magnetic field? would copper filing be equally satisfactory? why is it desirable to tap the glass plate? why is it desirable to use very few filings? what is the method for mapping a magnetic field by the use of a small compass?
- lyka (age 19)
cebu
A:
Iron is one of the ferromagnetic elements. Each iron filing consists of numerous magnetic domains. It turns out these domains can lower their energy by lining up with their fields along the skinny direction of the filing. Then the filing as a whole is a bar magnet, kind of like a compass needle, which can lower its energy by lining up with an external field. The effect should be enhanced by a tendency of the filings to line up end-to-end, influenced by each others' fields. If the filings are sitting on a glass plate friction can be too strong to let them rotate. Tapping reduces the friction temporarily. If you use too many filings they more or less form a uniformly magnetic sheet, losing any tendency to line up end-to-end, and also making something too thick to visualize clearly.
A compass needle is just a good example of a magnet that will line up in a field. If you had a lot of little compasses, they would be like your iron filings. If you have just one compass, you can just move it around to map out the field.
Copper is very weakly paramagnetic, which means there is a tiny effect of the same sign as in iron. I strongly doubt that you will ever notice even the slightest tendency of copper filing to line up in a magnetic field.