Are two magnets twice as strong as one?
Materials
This works best with wand magnets.
2 identical magnets.
Paper clips
Paper plates
Kitchen scale, measure in grams since most paper clips are almost a gram, the number is close to the real count of clips.
Spread out a pile of paper clips on a table. Each student starts a line in their journal as Case ‘A’. A few students try to lift as many clips as they can with one magnet. These counts are all recorded in the journals with one line for each try.
Before trying two magnets, ask the students to write down a prediction. Will two magnets pick up double the number of clips? We should take the highest number of clips that we could get with one magnet and add that number to itself. Double the single magnet number and ask students if two magnets will be that high.
Each student takes a turn to use two magnets to pick up as many clips as they can. When not their turn, students record the measurement on a new line for each other student.
What was the highest number for case A ?
What is that number doubled?
What was the highest number when using two magnets?
Are two magnets twice as strong as just one?
Is there a pattern in the numbers can we see?
What other patterns do you see?
The magnetic fields interfere with each other and while two magnets will be stronger than one, they lose efficiency when attracting each other.