PROBLEM: Can you vary the strength of an electromagnet?

PREDICTION:

MATERIALS: Two 1.2 volt batteries, battery holder, large nail, 2 pieces of insulated electrical wire, paperclips

PROCEDURE:

EXPERIMENT 1: Work in pairs to assemble your electromagnet.

A. Wrap about 10 coils of the wire tightly around the nail.
B. Attach each end (stripped of insulation) to the battery. (see diagram)
C. Test if the electromagnet works.

1. How many paperclips can you pick up?  (clips should be end to end so the test is the same)

2. Remove one of the wires from the battery, what happens?

EXPERIMENT 2: MAKING A STRONGER ELECTROMAGNET

A. Double the number of coils around the nail to a total of 20 coils.

3. How many paperclips can you pick up now?

4. Is that double the above number? 

5. If you triple the number of coils, how many paper clips can you lift?

B. Remove the nail from the wire coil.

6. Does the coil of wire still act as an electromagnet?

7. How many paperclips can you pick up now?

8. Any other observation

CONCLUSIONS: What happens when you make more coils on the nail?