10mm LED lights (You can also use 5mm- they are smaller, but still fun and actually last longer)
Lithium CR2032 3V coin cell battery
Strong magnets (We used neodymium magnets. You can also use strong ceramic magnets.)
Electrical tape
Scissors
Instructions
1. Start by pinching the leads of your LED over a coin cell battery. If it doesn’t light up, flip the battery over so the leads are touching the correct sides. 2. Cut a small piece of electrical tape and wrap it securely around the LED leads and battery. (The leads of the LED can be poky, so be sure to tape them down.) 3. Add a strong magnet on top of the taped battery. Tape it securely in place. 4. (Optional) You can also tape a piece of cardstock between one lead of your magnet and the tape surface. When you want to turn it off, slip a separate tiny piece of cardstock into this space between the lead and cardstock attached to the tape.
Science Behind It
The LED and the battery create an electrical current, flowing from positive through the light and continuing to the negative side of the battery where the circuit will repeat until the battery runs out of power. The inside of the battery is filled with electrolytes. It is a chemical medium that allows the flow of electrical charge between the cathode (the negatively charged electrode) and anode (the positively charged electrode). When a device is connected to a battery — a light bulb or an electric circuit — chemical reactions occur on the electrodes that create a flow of electrical energy to the device.
Tips
This is a fairly quick and easy project for members to complete, so we recommend you do this project while you are waiting on a different experiment or after a club meeting.