7th Grade Science
Building An Electromagnet
Question: What factors affect the strength of an electromagnet?
Hypothesis:
Materials:
A piece of wire
1 D cell battery
Some paper clips
An iron nail
Procedure:
Part A
1. Wrap the wire around the nail so that there are FIVE coils around the nail.
2. Connect each end of the wire to each end of the battery. Use the picture in your notes if you need
help constructing your electromagnet.
3. Stick the end of the nail into a small pile of paper clips and then lift up.
4. In the data table, record how many paper clips your electromagnet picked up.
5. Repeat steps 1- 4, increasing the number of coils by five each time until you have tested your
electromagnet with 20 coils.
Data:
ONE BATTERY
Number of Coils
5
Number of Paper Clips Picked Up
10
15
20
Part B
(We will do as a class demonstration.)
Repeat all of the steps as Part A, but use 2 batteries instead of just 1. Be sure to complete the data table
below.
TWO BATTERIES
Number of Coils
5
10
15
20
Number of Paper Clips Picked Up
7th Grade Science
Building An Electromagnet
Analysis:
Make a double line graph of your data below. You should put the independent variable (number of coils)
on the x-axis and the dependent variable (number of paper clips) on the y-axis. Make one line for your
Part A data (one battery) and another line for your Part B data (two batteries). Be sure to make a key to
indicate which line is for one battery and which line is for two batteries.
Conclusions:
1. What are the three main parts of an electromagnet?
2. What happened to the strength (number of paper clips picked up) of your electromagnet as you
increased the number of coils?
3. How did your data for one battery compare to your data for two batteries?
4. What happened to the strength (number of paper clips picked up) when the number of batteries
was increased?