At explainthatstuff.com there is a great explanation of magnetism and magnetic fields for kids by Chris Woodford. If you read that first you will get more out of this post. At the bottom of this post I’ve included a link to a more advanced video on magnetic fields from khanacademy.org for those who want a more detailed explanation.
Now let’s play…
Let’s explore the magnetic field or region of space around magnets in which the magnetic force occurs to get some insight into what it is like and how it works. Most of the time magnetic fields are invisible to our eyes. The demonstrations in the following videos help us to see the lines and curves of force of magnetic fields around different types of magnets.
First is this video from funlearners channel on YouTube:
Here we can see some slices through the magnetic field with all of the little compass pointers on the plexiglass lining up. Plus we can see that the magnetic field changes shape with the two differently shaped magnets. You really get a sense of the 3-D shape of the field when the bar magnet is in the middle and the man spins the viewer.
Here is a 3-D magnetic field viewer by wbeaty that you can make yourself:
Easy peasy! Try not to touch the steel wool slivers that you cut off too much. Instead of picking them up with your fingers just cut them over a sheet paper and then pour them into the bottle down the crease of the paper folded in two. Also, rinse your fingers after working with the steel wool to avoid nasty metal slivers in your skin or eyes.
Experiment with your 3-D magnetic field viewer using one, two or more magnets. Try different shapes and types of magnets to see if and how the fields differ. Carry your viewer around the house and see if you can spot a hidden magnetic field. Then try to figure out what is causing it.
This video from KJMagneticsProducts is what happens when you stick a powerful magnet into magnetic paint:
That magnet is going to be hard to get clean again. That paint is wet, but the particles of iron pile up on each other in the shape of the lines and curves of the magnetic field until it looks solid. There are many videos on the internet showing ferrofluids, which are liquids that become strongly magnetized by a magnetic field. Ferrofluids display the beautiful geometries and movement of magnetic fields. We will revisit ferrofluids in a future post on OGLoA. Until then, go look them up. You won’t be sorry!
For the older kids, if you have an old-style computer monitor just lying around, research how it can be made into a magnetic field viewer. Get permission from your parents first! Here is a great one featured in this video by YoungTesla:
Move over LavaLite, we’re going to make one for parties! YoungTesla has three magnet/computer monitor experiments on his YouTube channel and lots more. Check it out.
As promised here is more on magnets and magnetic fields from KhanAcademy.org:
Khan Academy is a wonderful web site for self-study or to use as another source of information when you are stuck on a topic in your school work.