In this lab, students will build an electromagnet. They will make adjustments to both the size of the solenoid and the amount of current to examine how that changes the strength of the electromagnet.
Included in your purchase is both the student handout as well as a teacher key. The key includes helpful comments/advice for the various stages of the lab as well as answers to the conclusion questions.
This lab is relatively affordable if you're purchasing supplies on your own (depending on your class size). You'll need 2 D batteries per group, insulated wire (maybe like a meter-ish per group), and a large nail. Everything is reusable (well, the batteries die eventually, but you'll get plenty of use of out them before then). Oh and paper clips, but what teacher doesn't have those on hand?
Other labs to check out:
Balloon Rocket Lab for Newton's Laws
Building Circuits Lab