100mm (4") Bar Magnet

SKU: 33540

$0.45USD or lower Each

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[2.8]   2 Reviews    | Write a Review

The 100mm (4") long ferrite bar magnet can be used for standard physics lab experiments in understanding the nature of magnetic fields. Sold individually for simple paper clip pickup experiments so buy 2 for attraction/repulsion.

See our blog on Magnet Experiments for Kids for more information and ideas.


Repulsion Test

Two 100x20x7mm bar magnets were placed in contact with opposing poles (N:N). They were released and the distance caused by the repulsive force was measured.

Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Average
30mm 36mm 35mm 35mm 31mm 33mm


Paperclip Pickup Test

Forty paper clips were placed in a 500ml beaker. A single 100x20x7mm ferrite bar magnet was dipped into the beaker to pick up as many paper clips as possible.

Type Trial 1 Trial 2 Trial 3 Trial 4 Trial 5 Average
Uncoated Steel 27 21 21 26 25 24
Plastic Coated Steel 14 13 12 11 11 12

Magnet Experiment Video

If you need bar shaped magnets with greater holding or repelling force, see: neodymium magnet blocks.
  • Use for repulsion-attraction
  • Will not demagnetize when pushed together
  • Stamped "N" & "S" & painted red & blue respectively
  • Paint is guaranteed lead & heavy metal free
  • Will pick up minimum of 20 uncoated paperclips
  • Note (1): Ferrite bars are fragile/brittle. Do not drop on hard floors.
  • Note (2): Ferrite bars are relatively weak & will not magnetize nails or pins. Stronger magnets such as Nd or Alnico are best for this application.
Reviews (2)

These bar magnets are totally useless. they barely pick them selves. I gave these to my grandson, they look nice but even he was disappointed compared to the nd rare earth magnets. Maybe I'm missing something here, if I'm, wrong please tell me

— William
— Indigo:

These ferrite bar magnets are intended solely for picking up light weight objects like paper clips, moving iron filings or demonstrating attraction/repulsion. An Nd bar magnet that size would cost $50 vs the $1.00 you paid. They are also child safe. Nd magnets this size would snap together with such force that they would break a child's finger. We did the paper clip pickup test as outlined in Magnet Experiments for Kids after seeing an Amazon review complained their ferrite bar magnets could barely lift a single paper clip. The product & its review disappeared the day after our blog was published. You couldn't have bought a better magnet for your grandson.

Great magnets! I ordered a bunch for my classroom, they arrived quickly and have held up nicely. Great product and service, I would definitely order from indigo again.
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