Magnets
Magnetic forces are known since 6th century B.C.
Permanent magnets made from: Co, Ni,Fe
each magnet has two poles: (south and north)
Like poles repel; unlike poles attract
Difference with electric phenomena: the poles of a magnet cannot be separated (no magnetic monopole)
Similarity with electric phenomena: magnets are surrounded by magnetic fields
- the magnetic field can be detected using a small compass
- the compass points in the direction of the field lines
- iron filings line up also in the direction of the magnetic field
- strength of the magnetic field ~ density of field lines