Activity: Build a Flashlight
How do I store lithium batteries?
There are some precautions you may want to take in storing your lithium batteries. This document provides information on safe battery storage: Battery Storage
Can I reuse the LEDs and the batteries from year to year? How about from class to class?
You can definitely reuse the batteries and LED lights. It's important to store them cautiously so that they are not in contact with a conductor (ex: aluminum foil/metals) and not in contact with the LED lights.
What if we have trouble with the aluminum foil?
When students experiment with the aluminum foil, we want them to learn how to extend their knowledge and use the aluminum foil to connect the long leg to the plus side, and the short leg to the minus side. The aluminum foil is acting like a wire. When they make their flashlight with the card, we are asking them to figure out how to use those aluminum foil wires to connect the LED to the battery in a way that lets them connect and disconnect easily (to make an on/off switch.) We recommend watching this video in the Extensions slide for tips on turning the flashlight on and off: What if there was no electricity?
Will Christmas light replacement bulbs that work with a 9 volt battery work for this?
There's so much variation in Christmas bulbs, so we hesitate to predict whether or not the experiment will be successful, but it's worth a try! If you are choosing among bulb colors, we suggest trying the red ones first as they tend to work with lower voltage.