After researching into the Arduino’s capabilities, it is not going to be possible to have an electro magnetic current running through as there is not enough power in the Arduino and it could cause a lot of damage if completed wrong. So my revised idea is to have a motor with magnets on the end of rods, and a Ping sensor that determines how close or far away someone is which will change the speed in which the motor rotates.
(Please excuse my drawing skills!)
I feel that although this is still going to be challenging for me as I am new to Arduino, it is going to be one of the simplest approaches I could do with the outcome being very effective. The audience will have to engage with it in order for it to do anything, and I feel the use of ferrofluid will be very new to most people.