Design #1 Materials Iron nail, D-cell battery, 100
used
cm wire, switch
Switch
Yes
present
Design #2
Iron nail, 9-volt battery, 250
cm wire, switch
Design #3
Iron nail, 9-volt
battery, 120 cm wire
Design #4
2 iron nails, D-cell batteries, 150
cm wire, switch
Yes
No
Yes
Mass
Lifted
14g
40g
289
30g
Electromagnets are used in junk yards and recycling plants to pick up and move metal objects. The more strength the
electromagnet has, the greater the mass it can move. Ms. Hui challenged her students to build an electromagnet that could lift a
mass of at least 20 grams. To simulate the metal found at a recycling plant, the students were given assorted iron masses that
their magnet had to pick up. Since an electromagnet requires electricity to control it and turn it on or off, the students had
assorted batteries to work with as well as switches. Their job was to find the right design and orientation of the wire so that its
magnetic field works just like a regular magnet, but you can turn it on and off, and it must pick up at least 20 grams of iron.
One group clearly won the challenge. What aspects of the winning design accounted for the strength of Group #2's electromagnet?
A)
They used a 9-volt battery for more electrical energy.
B)
More turns of wire around the core and the maximum voltage.
C)
Using a double-nail core and more turns of wire around that core.
D)
Keeping the switch on all the time instead of turning it off and on