A fifth grade class has collected empty cans for recycling. They have several large bins with aluminum and steel cans, all mixed together. The two types of cans must be separated. Which of the following techniques could the students use to separate the two types of cans?
Place the cans in water, and the aluminum cans will float
Crush the cans to make them easier to carry
Test the cans for their ability to conduct electricity
Use a magnet to find and remove the steel cans