Hello parents, teachers and students! Are you looking for something fun to do at home that has a little bit of science behind it? Learn how to make index card flashlights at home with Meteorologist Sarah Spivey.
Be sure to check out GMSA@9 on Wednesdays when Meteorologist Sarah Spivey does the demonstrations and explains the science behind it.
HERE’S WHAT YOU’LL NEED
- An index card
- Aluminum foil
- File folder labels (We’ll use these as tape. They are stickier, easier to tear into smaller pieces, and more shareable than a roll of tape)
DO THE EXPERIMENT
- STEP 1: Start by locating the positive wire on the LED bulb. It’s the longer of the two wires.
- STEP 2: Using a small piece of file folder label, tape the LED bulb to the index card, leaving plenty of room at the bottom of the wires. Make sure you leave plenty of the wires exposed so that they can make good contact with the aluminum foil, which will be the conductor for our flashlight. On the index card, mark which side of the card contains the positive wire and which side of the card contains the negative wire. See the figure below.
- STEP 3: Take a piece of aluminum foil and fold it over “hotdog” style so that you end up with a skinny, long piece of aluminum foil.
- STEP 4: Tape one end of the aluminum foil to the positive end of the LED light bulb. Then tear or cut the aluminum foil strip so that about the bottom third of the index card is not covered with aluminum foil.
- STEP 5: Place the button battery, positive side down, onto the aluminum foil strip. Using two pieces of a file folder label, tape the battery to the index card. Make sure to leave some of the textured, negative side of the battery exposed. See image below.
- STEP 6: Flip the index card. On the negative side of the index card, tape the remainder of the aluminum foil strip to the negative wire of the LED bulb.
- STEP 7: Complete the circuit and turn on the bulb by bringing the longer piece of aluminum foil into contact with the battery on the other side of the index card. Your lightbulb should turn on.
HOW IT WORKS
This is a great example of how circuits work, and it shows that aluminum foil is a good conductor of electricity!
The positive side of the index card is charged by the positive side of the battery. However, the light bulb doesn’t turn on until the circuit is complete. This happens when the other side of the index card comes in contact with the negative side of the battery through the conductive aluminum foil.
If you find that the lightbulb is not turning on, try some troubleshooting. First, make sure enough of the textured, negative side of the battery is exposed (Step 5). Second, ensure that sufficient contact is made between the lightbulb wires and the aluminum foil (Step 2).
SCIENCE WITH SARAH
If you’d like Sarah to come to your school and conduct a science experiment live on KSAT, fill out this form. “Winners” are selected at random.