Science Monday: Rotating Switch

Tonight we started science experiments again after our summer break. We’ll be doing a bunch of biology stuff this year, but those experiments don’t start until about week 7, so in the mean time we’re catching up on some left over experiments from last year.

Tonight we talked about electricity. We’ve previously talked about batteries (electron buckets), and circuits (the hoses between the buckets). Tonight we talked about switches.

We were making a very special kind of switch: a rotating one.

We first put strips of aluminum foil on a cardboard toilet paper roll.

We then closed up the ends and stuck a dowel through the center.

After that we took the roll and used a box to hold the ends, so that the tube could rotate freely.

After that, we used two pieces of wires as the contacts that would rub against the tube. We hooked these contacts to a battery and light bulb, and then rotated our switch.

When the contacts touched the aluminum foil strip, it would close the circuit and the light would turn on. When the contacts just touched the cardboard tube, the light turns off because cardboard is an insulator.

We then hooked a buzzer across the terminals of the light bulb (in parallel, but we haven’t talked about that yet.), and so not only did the light blink on and off, we also heard the buzzer beep when we spun our rotating switch.