For this assignment, I have created an electrical switch that uses water to switch on and off. Unlike conventional mechanical switches that require us to use our hands, this switch uses water. As shown below, this switch has two wires that are taped to each other.
Without a conductive medium, i.e. water, in between them, electricity will not flow because air has high resistance. Only when both wires touch water, the circuit will be closed and LED will turn on. Shown below is a video of me turning LED on and off using this switch.
Reflection / Future Improvements
One advantage of this switch over other conventional switches is that resistors can be removed from the circuit. Since medium is required for the switch to operate, the medium itself can act as a resistor. By controlling the resistance of the medium (e.g. adding salt to water), user can freely control the brightness of the LED.
One of the many aspects of this switch to improve is finding a way not to make water droplets to remain on the wires even when they are removed from the water. Because water adheres to wires, I realized the LED will be on even when the wires are pulled off from the water. One possible solution to this would be making the gap between the wires larger, so water droplets on the wire cannot close the circuit.