Magnetism is invisible, but it’s all around us.
There is a giant magnetic field on Earth.
But in this experiment, we will see a smaller version of magnetic field.
We will use iron filings to see the magnetic field in 3-dimension.
(Here’s an example on 2-dimensional magnetic force field.)
Magnet attracts iron and the magnetism can act through many materials such as paper, cellophane, plastic or glass..
They spread over the space by aligning themselves with the magnet’s force field.
- a few strong magnets (neodymium magnets, a rare earth metal, are very strong magnets)
- iron filings
- adult supervision
- a clear bottle (can be glass or plastic)
- Tape the strong magnets on the opposite sides of the bottle. Make sure the opposite poles are facing each other (e.g. N with S, or S with N).
- Poor iron filings into the bottle and then close the cap.
- Rotate the bottle so that iron filings are stuck on both sides of the bottle where the magnets are.
- Observe how the filings move and distribute.
- Move the bottle to another position and see how the iron filings move with it.
- If you don't have a clear bottle, you can also use a piece of paper or in our case, we used a sheet of cellophane at the beginning. It's also spectacular since you can see it up close.
So what you see is the outline of the 3-dimensional magnetic field.
But the magnetic field is not the only force at play here.
There is also gravity.
When you rotate the bottle, you can see the iron filings move around responding to the change in gravitational force.