Secret Messages

You probably know about Teflon® - it's that stuff used on nonstick pans to make them nonstick. But you might not know that Teflon® is also made into "Thread Seal Tape" used by plumbers - or anybody who fixes leaky faucets or changes a shower head. Before screwing a metal pipe onto another metal pipe, they wrap a piece of this tape around the threads first. It stretches a little and makes a great seal - much better than metal-on-metal. And, since it's slippery, the pipes are easier to screw together - no more scritchy scrapiness.

You can find Teflon® tape in any store that sells plumbing supplies (most hardware stores will have it). Teflon® is a trade name (from DuPont), so you might see it under "PTFE" for PolyTetraFluoroEthylene, its official scientific name.


  • PTFE Thread Seal Tape (Teflon tape), any width
  • ruler
  • ball point pen (These work the best. Other pens will work too, but might be smeary.)
  • paper
  • scissors
  • This is fun to do with a buddy!


  1. Using scissors, cut a length of tape about 6 to 8 inches or 20 cm long, and lay it flat on top of a piece of paper.
  2. Measure the length and width of the tape and write them down.
  3. Carefully write a secret message on the tape. (Hint: Use a light touch. You might need to experiment a little to get it the way you like it. Also, it's best to leave a couple of centimeters blank on each end of the tape - you'll see why later!)
  4. Gently pull the tape sideways where you've written the message. It will stretch like crazy. Don't pull too hard, though - it can pull apart, then you might have to start over.
  5. You now have a secret message! Measure the tape again and write down your measurements.
  6. Trade messages with your buddy.
  7. Hold the (original) ends of the tape, and pull gently to see the message.
  8. Measure the tapes again. Did they return back to their original sizes?
Pretty cool, huh?

Click on the image below to see my secret message to you !
secret message

So, how does this work?

When the PTFE is made into a tape, all of its polymer chains get ordered, or lined up, like this:

Like fibers, that makes the tape much stronger in one direction than another. See the page on fibers for more!

More Fun with PTFE Tape!

This tape is made out of a pretty special polymer. What else would you like to know about it? What is this stuff capable of?

Think about a question that you'd like to ask about this stuff, and write the question down.

Now, what would you need to do find the answer?

Jot down the steps you'll need to take before starting. (This can really help to make what you're going to do be very clear.)

Look over what you've written, and think about safety. Are any of the steps unsafe? Is there anything that you need, like goggles or gloves, to be safe? Always think about safety before you try new things!

Do it, and write down what you've found out.

Hey, you just did science! Cool !

Did you find out something neat? Send it to us, and we'll post some of the experiments and results here on this web site !
Click here to send us an email with your info. Thanks!

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