posted by Beret
Weather systems appear to have gone haywire.
I won’t mention that it’s been unseasonably warm and sunny here, because people suffering in winter wonderland get a little huffy about that. They’ll have the last laugh when I sink into the ocean, though.
Whatever the weather, it never hurts to be prepared. Below are instructions for making an unbelievably simple flashlight that can live in your wallet/backpack/glove compartment/bedside table. You will be ready for any power outage, midnight snack emergency, or for when you drop a $20 bill in a dark movie theater. NEVER use this to illuminate the bottom of your theater seat, however. Nothing can prepare you for what lurks there.
What you need:
*3-volt coin battery (aka, a button cell). Ask for CR2032. I got mine at Radio Shack for about $4, simply because I didn’t want to wait a week or drive to Target. You can find them for much cheaper online and at bigger chain stores.
*3-volt LED bulb. I found at these Radio Shack for about a dollar. They are also at hobby shops, and online for even less. Be forewarned: the packages don’t necessarily say clearly, “3 Volt LED.” In fact, the packages are a bit confusing to someone who doesn’t hang around at Radio Shack very often. If you’re lucky, it might list the minimum and maximum voltage. I used a 5mm bulb that said 2.4 Volt max, however, and nothing blew up when I connected it to my little lithium battery. I think the secret is to avoid a 12-volt LED, because your 3V battery probably can’t power that thing.
*A sheet of self-adhesive foam, used for a variety of crafts. You can find these on Amazon, at craft stores like JoAnn Fabric and Craft, or in the art supplies section at places like Target. You can also use non-stick foam, and then use a decent glue or Zots to stick it together. No problem.
1. Cut out four squares of foam, measuring 1 1/2 inches on each side.
2. On two of the squares, trace the battery in the center.
3. Fold in half, and cut out the circles.
4. Peel off the backing and stick those two pieces together. Nestle the battery into the foam sandwich.
5. Slide the LED onto the battery sandwich, with the longer end of the LED paired with the positive side of the battery. Squeeze the ends to the battery to test and make sure the LED lights. Note: it’s ok to touch this thing with your bare fingers. I was very, very nervous to do so, but lived to tell.
6. Peel off the backing from a circle, and place the backing over one of the LED ends. Then, peel the backing from a square and place over the circle.
7. Repeat step 6 on the other side of the battery.
9. When you want to turn on the flashlight, squeeze in the center. To turn off, simply let go.
For more information about LEDs, check out the awesome video blog from Mr. O! at the Children’s Museum of Houston. His short video discusses light emitting diodes, how they work, how they compare to incandescent bulbs, and what is electroluminescence, anyway? Mr. O! has posted many more great science activities there, including the Marshmallow Blaster, which looks like good fun. Not particularly helpful in a power outage, however.