Magnet strength test: a 35-minute 3rd grade forces experiment
What it is: a 3rd grade forces experiment where students test which magnet is strongest by counting how many paper clips it can hold in a chain, and then whether magnets still attract through paper, cardboard and fabric. Students practice fair tests and recording data in a table.
Time: about 35 minutes. Grade: 3rd grade.
Materials: 3 or 4 different magnets per group (bar, horseshoe, ring, fridge magnet), a box of small metal paper clips, a sheet of paper, cardboard, a piece of fabric, and a data table.
- Ask: "How could we find out which magnet is strongest?" Agree on a fair test: same paper clips, same way of hanging them.
- Groups predict, then hang paper clips in a chain from each magnet until no more stay on. They record the number.
- Groups repeat each test once more and compare results.
- Next, they test the strongest magnet through paper, cardboard and fabric.
- Groups make a bar graph and answer: "Does size tell you how strong a magnet is?"
Safety: keep magnets away from phones, computers and cards. Small magnets should stay on the tables, and anyone who finds a loose magnet gives it to the teacher.
Differentiation: students who need support test 2 magnets with a partner. Students who are ready measure the distance at which a magnet first pulls a clip. English learners can use the words attract, strong, weak and through.
Quick check: ask a student which magnet was strongest and what evidence they have.
Need it for another grade or subject? Ask us on the request page and our team will write it.
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About this resource
- Shared by
- @UpOnlyLearning · Curriculum team
- Posted
- Oct 30, 2026
- Type
- Lesson plan
- Grade
- Grades 3–5
- Subject
- Science
- Language
- English
- License
- Free for classroom, co-op and tutoring use. Please don't resell.