We are John, Peter, and Neil.
We make all of your magnet-related dreams come true.
FAQ – Magnicians Display (seen at Maker Faire)
What is this?
It’s a fish tank with electromagnets in it.
You can see the magnetic field because the water in the tank contains tiny nickel-alloy shavings and is illuminated by an array of LED lights. Activating the electromagnets causes the particles to orient themselves along the lines of the magnetic fields, and their intrinsic reflectivity allows you to see this otherwise invisible phenomenon.
What am I seeing?
You’re seeing the magnetic fields of the electromagnets.
The fields appear to be pulsing or moving (if it’s turned on) because the small microcontroller connected to the amplifier is sending variable amounts of current to each magnet.
How does it work?
We built a large amplifier to power the magnets. It is controlled by an Arduino Uno. Each magnet is drawing about 250 watts of power at 24 volts.
What’s in the water?
Small particles of nickel, suspended in soapy water which is circulated by the two pumps in the back corners of the tank.
When nickel alloy flake is mixed with a surfactant (we used simple dish soap and water), it becomes a type of ferrofluid. Ferrofluids are colloidal liquids made of nanoscale ferromagnetic particles suspended in a carrier fluid (usually an organic solvent) and each tiny particle is coated with a surfactant to inhibit clumping. Our suspension is not perfectly balanced. That means we have to stir it from time to time because the nickel bits will eventually sink to the bottom. A fancy, perfectly made ferrofluid (the kind used in suspension systems and other industrial applications) would not settle out or would do so over a very long period of time.
Can you build me one like this?
Yes. Send us an email at firstname.lastname@example.org
Can I buy a smaller one?
Hopefully in a year or so. We’re starting a project to make a commercial version of this.