Question: How does ferrofluid work, and how is it magnetised?

Jarvist Moore Frost answered on 12 Mar 2012:

I think what you have is lots of little particles of iron (much smaller than iron filings) which are wrapped up in little coatings of some kind of soap and then dissolved in a liquid. The soap stops the iron sticking together into one big clump (which is what it will try to do when you put a magnet near it!) and so it stays liquid.
They’re really cool though, aren’t they?

Another fluid that you can make at home which is so INCREDIBLY weird is a non-newtonian fluid out of corn starch mixed with water. If you get the amounts right, you have a material that thickens with shear forces, so you can juggle it in your hands, and bounce it, but then when you stop it turns into a liquid and falls through your fingers. To make the maximum mess, you can make this fluid & then put it on an up-turned speaker and play strong base music through it to make it hold crazy acoustic waves. If you try this I recommend doing it in the bath tub so you can easily wash it down!