@Vidar
Actually I believe there are various different viscosities of ferrofluids.
The ones used in magnet clutches- magnetic rheological fluid -
completely hardens to lock the two clutch disks together when
the magnet is fully asserted. There are a number of fascinating
you-tube videos having to do with ferro fluid control and
sculptures that seem nearly alive. It may be possible to dilute
some fluids down using the right solvent vehicle.
---
Here one proposed experiment I remember, that you might try;
Water floats above the ferrofluid that has been enabled by a magnet.
So you have effectively a fluidic trap door below the water. It will expel
the water.
You have a chain of ping pong balls that float up through the fluid
and then up through the water. The water can be made arbitrarily
deep so as to put arbitrarily large force on the next (lowest) ball
of the chain entering the device from underneath. If one then
connects the ends of the chain you will have a self running device.
:S:MarkSCoffman
