Purpose
Investigate the properties of permanent magnets.
Concept
There are two kinds of magnets, permanent and temporary. The magnetism in permanent magnets happens at the microscopic level. Unlike electrical charges, magnets always have two poles, called North and South.
Materials
Magnetic compass, 2 nails, 2 bar magnets, iron filings, sheet of paper.
Procedure A. Compass and Magnet Check
1. Check the compass by holding the south end of the bar magnet near the compass. The north end of the compass needle should point towards the bar magnet.
2. Repeat with the other bar magnet.
B. Induced Magnetism
1. Rub a nail against the bar magnet.
2. Touch the nail to the other nail.
3. Observe and record what happens.
4. Bring the nail near the compass.
5. Check the nail to see if it has both, a north and a south pole.
C. Magnetic Field - one magnet
1. Place a bar magnet on the table and cover it with a sheet of notebook paper.
2. Sprinkle iron filings on the paper.
3. Gently tap the paper with your finger.
4. Make a drawing of any pattern that appears.
5. Explore the magnetic field by following the pattern lines with the compass.
D. Magnetic Fields - north to north
1. Repeat part C with both magnets under the paper. Place the magnets so the north poles are facing each other.
2. Make a drawing of any pattern that appears.
E. Magnetic Fields - north to south
1. Repeat part C with both magnets under the paper. Place the magnets so the north pole is facing the south pole.
2. Make a drawing of any pattern that appears.
Analysis
1. Was magnetism induced in the nail? Explain.
2. How many poles were induced in the nail?
3. Where, around a magnet, are the magnetic field lines most concentrated?
