Smoke Magic Trick - Smoking Fingers

Smoke That Appears As If By Magic

Although the smoke magic trick looks awesome if you use your hands, you may wish to wear disposable plastic gloves to avoid absorbing phosphorus through your skin.
Although the smoke magic trick looks awesome if you use your hands, you may wish to wear disposable plastic gloves to avoid absorbing phosphorus through your skin. Sam Bloomberg-Rissman / Getty Images

Would you like to try a simple smoke magic trick? It easy to make your fingers smoke when you rub them together and glow in the dark. All you need is a matchbox and a way to burn the striker portion. There's also a video of the smoking fingers project, if you'd like to see what to expect.

Difficulty: Easy

Time Required: about a minute

What You Need:

  • matchbox of safety matches
  • cold water faucet or chilled pan
  • scissors
  • lighter

Perform the Smoke Magic Trick

  1. Cut out the striker portion of a matchbox from a box of safety matches. Trim off any paper around the striker.
  2. Fold the striker in half, striker-sides facing each other.
  3. Set the folded striker on top of the running cold water faucet or a refrigerated metal pan.
  4. Use a lighter to set fire to the striker. Ignite both ends. Then run the lighter along the length of the folded striker. It won't burn to ash, which is fine.
  5. Discard the burned striker.
  6. You will see a brown residue that has been deposited along the top of the faucet or metal pan. Run your fingertip along the residue to pick it up.
  7. Slowly rub your finger and thumb together. If you do this in the dark, your fingers will have a greenish glow. Very, very cool.

Tips:

  1. Wash your hands after doing this, and try to avoid breathing in the smoke. The trick probably involves white phosphorus, which can be absorbed through your skin and is toxic.
  1. If you don't have scissors, you can do this trick by tearing off the striker portion of the matchbox with your fingers. It's just easier to cut out the striker, if you can.
  2. You could use the matches in the matchbox, rather than a lighter, of course.

How the Smoking Fingers Trick Works

Are you interested in the science behind this smoke trick?

It's commonly believed the smoke is vaporized white phosphorus. Here's how it works:

Phosphorus is a chemical element that can take several forms, called allotropes. The type of phosphorus in the striker of match boxes is red phosphorus. When you burn the striker, the phosphorus is vaporized and condenses into a solid onto the cool metal surface. This is white phosphorus. The element has not changed identify -- just the structural arrangement of the atoms. Rubbing your fingers together produces enough heat from friction to vaporize the phosphorus into what appears to be smoke.

White phosphorus readily reacts with oxygen in air to form a flammable compound. Because of this, one of the earliest uses of the purified element was to make matches. Early friction matches have been around since Robert Boyle made them back in 1680, although they did not become popular until 1830. The early phosphorus-based matches were dangerous, containing enough phosphorus to poison a person. Modern matches are called "safety" matches because they don't use highly toxic chemicals.

Smoke Trick Safety

The smoking fingers trick used to be a popular school science demonstration. It is not performed much any more because of concerns about the risk from the phosphorus, but if you do the trick infrequently, the dose of phosphorus is small.

You can lessen the exposure by wearing thin, disposable gloves and taking care not to breathe the vapor.