For my engineering class I am creating a kit that can be used to teach/demonstrate magnetism to children. My idea involves cutting the current going through the circuit so the electromagnet loses around half it's power. Sadly I'm no good with electronics and don't know what to do.
I figure I'll be using:
~10 ft of wire
two 9v batteries wired in series
So the idea is the battery -> on/off switch -> a selector switch (DPST) ->one path goes straight to the wrapping wire and the other goes through a resistor before going to the wrapping wire and connecting back to the battery.
My issues are that from my calculations I'm working with around 78.5 watts and no resistors can handle that from my understanding. How do I go about lowering the amperage if I can't use resistors due to watts?
I figure I'll be using:
~10 ft of wire
two 9v batteries wired in series
So the idea is the battery -> on/off switch -> a selector switch (DPST) ->one path goes straight to the wrapping wire and the other goes through a resistor before going to the wrapping wire and connecting back to the battery.
My issues are that from my calculations I'm working with around 78.5 watts and no resistors can handle that from my understanding. How do I go about lowering the amperage if I can't use resistors due to watts?