Experiment to Investigate which Factors Affect the Strength of an Electromagnet

The variables are the number of coils and the strength of the magnet. The number of coils I will change is in the independent variable and the strength of the magnet is the dependent variable.

What I Intend to do

I intend to investigate which factors affect the strength of an electromagnet. I intend to keep the voltage the same throughout the experiment I'm going to keep adding coils to the solanoid and find out how many paper clips it attracts.

Apparatus

Power Supply DC 0 - 13v demagnetising solanoid

Connecting wires with plugs

Crocodile clips

Insulating wire (approximately 1m)

Nail (soft iron)

Heat proof mat

Stand and clamp

Paper clips

Circuit Diagram

Preliminary Experiment

In the preliminary experiment I will check the circuit to see if it works. I will also check the voltage and how many coils (for start).

Obtaining Evidence

No. of Coils

No. of Coils

0

9

20

43

30

25

40

46

50

47

60

50

70

50

80

50

90

50

00

50

No. of Coils

No. of Coils

0

2

5

7

20

33

25

38

30

40

35

42

40

45

45

47

50

49

55

50

Analysing Evidence

I have found simply that the more coils there are the more paper clips are attracted. On average each set of 5 coils attracts 37.3 paper clips. I have identified that the strength increases with the number of coils and the graph is non-linear. The number of coils increases the strength because of the domain theory. Due to there being more coils on the nail there is more power going through it so will become more magnetised allowing it to pick up more paper clips. The more coils meant more attracted clips as portrayed in our prediction so our results support our prediction.

Evaluating Evidence

The procedure was relatively easy although I thought we didn't have enough time to complete the experiment. Our experiment was fairly accurate except our preliminary experiment results were anomalous in some places because there was one point when we added coils and the number of paper clips went down. The variables were kept constant and the reliability of the experiment could have been improved if we could have acquired more results. The evidence is sufficient to support a firm conclusion although the nail could have been magnetised because of past experiments. The experiment could be improved by extending the time, the length wire, and the amount of paper clips. A longer nail could be included as well as using a Newton meter and better timing could also be used. To extend the enquiry I suggest looking at the voltage and other materials.

Lliam Heavey Physics Coursework