The strength of an electromagnet depends on several factors, including the number of coils wrapped around the coil and the voltage of the power source. The greater the number of coils, the stronger the electromagnet. And, the greater the voltage, the stronger the electromagnet. Scenario
A group of students has been testing electromagnets in the lab. They made the electromagnet by wrapping copper wire around a nail. For one of the tests, they wrapped the wire around the nail 25 times. For the second set of tests, they wrapped the wire around the nail 50 times. They also have 4 different batteries: 1.5 V, 3.0 V, 4.5 V, and 6.0 V. They used their electromagnets to see how many paperclips each can pick up.

Data
For each electromagnet, two trials were conducted at each voltage. The data was recorded in the tables below.

25-turn Electromagnet

Battery voltage
Number of paper clips picked up
Trial 1
Trial 2
Average
1.5 V
5
7
6
3.0 V
12
12
12
4.5 V
14
17
15.5
6.0 V
20
26
23

50-turn Electromagnet

Battery voltage
Number of paper clips picked up
Trial 1
Trial 2
Average
1.5 V
10
16
13
3.0 V
28
24
26
4.5 V
30
32
31
6.0 V
44
50
47

Graphing Data
Make a line graph of the data found above. On the same graph, show the average number of paper clips each electromagnet picked up for each voltage tested. Plot the voltage on the x-axis and the average number of paperclips picked up on the y-axis. Scale the x-axis in intervals of 1.5 volts and the scale for the y-axis in intervals of 5 paper clips.

Questions
Look at the data table and the graph for the 25-coil electromagnet. With the 1.5 V battery, the electromagnet picked up an average of 6 paper clips, and with the 6.0 V battery, it picked up an average of 23 paper clips.
About how many times stronger than the 1.5 V battery is the 6.0 V battery?

What is the approximate ratio of the number of paper clips picked up using the 6.0 V battery to the number of paper clips picked up using the 1.5 V battery?

Is this a direct relationship or an indirect relationship?

Look at the data table and the graph for the 50-coil electromagnet. With the 1.5 V battery, the electromagnet picked up an average of 13 paper clips, while the 25-coil electromagnet picked up an average of 6 paper clips.
What is the ratio of the number of turns of the 50-coil electromagnet to the number of turns of the 25-coil electromagnet?

What is the approximate ratio of the number of paper clips picked up by the 50-coil electromagnet to the number of paper clips picked up by the 25-coil electromagnet?

What does doubling the number of coils do to the strength of the electromagnet?

What does double the voltage do to the strength of the electromagnet?

Using the graph, predict how many paper clips a 7.5 V battery would pick up for both the 25-coil electromagnet and the 50-coil electromagnet. Explain your reasoning for your prediction.