The Floating Cup





Introduction: The Floating Cup

About: I have the best job ever! I get to do science assemblies for elementary schools and after school science programs along with science summer camps and birthday parties! I love learning new things and creat...

The Floating cup is a simple, yet very effective April Fools trick that you can use on your friends using a simple Styrofoam cup. They will be amazed that you can actually make the cup float in mid air. No matter how hard they try, they will not be able to match your ability.

Step 1:

What you will need:

1) Two Styrofoam cups

2) Piece of wool or cloth

3) Willing victim/helper


4) Fun Fly Stick ® toy

Step 2:

Begin by talking about static electricity and how two objects with the same charge will repel or “push away” from each other. If you have a Fun Fly Stick ® toy, demonstrate this effect now.The Fun Fly Stick is a toy that uses static electricity to charge a piece of Mylar, causing it to float as you hold the stick underneath it. This is a great way to "suck" your victim into believing that what you are about to show them actually works. If you do not have a Fun Fly Stick, just explain how two objects with the same electrical charge will repel each other.

Step 3:

Give your victim a Styrofoam cup. Take your cup and rub it on the piece of cloth for a few seconds. Now quickly rub your other hand on the cloth while explaining that you are building up a negative charge from all of the electrons in both your hands and the cup.

Step 4:

Without their knowledge, Carefully press your thumb into the back of the cup so that it is stuck to your thumb

Step 5:

While facing your victim, hold one hand under the cup and the other hand (the one with your thumb inserted into the cup) behind and somewhat over the top of the cup. Make sure that your thumb is pointing directly at the person so that it remains hidden behind the cup. Now move your hands apart so that your thumb is holding the cup in between your hands making it appear to float. You can add to the effect by slightly moving your hands around the cup and moving your thumb just slightly so that it appears that your hand movements are affecting the cup as it "floats" between your hands.

Watch as your victim now tries over and over again and, no matter how hard they try, they will not be able to get their cup to float.



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    19 Discussions


    2 years ago


    super. magic

    it is so tricky to tell if it is stuck on your thumb

    In the original picture you can obviously see his thumb through the cup

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    Ha! Loved the video, and the lead-in was the perfect setup for this as a prank. I'm going to pull this on my kids. Thanks!

    This really needs to be broken up into more steps (you have ten separate steps within the introduction!), and absolutely needs more photos of what to actually do; TV screen-grabs can only convey so much, and don't really meet the terms of the site (you should use your own original images).

    6 replies


    Thanks for the input. When I originally wrote it, I used the screen grabs assuming that the video would be loaded and be included in the instuctions. Unfortunately, the video is still "processing" and is not included. I will update it later today....

    Thanks for the feedback.

    Oh, if you want an embedded video you should upload it to YouTube and then embed it here.

    Hang on, is that you in the video?? You're a TV Scientist?

    I own a business where we offer after school science programs and assemblies at schools as well as birthday parties. I also get to do an experiment every Saturday morning science on our local tv station to encourage kids to do science at home. They have "most" of the videos over the last year and a half at - just search for Radical Rick. This was my first attempt at an instructable, other than the Jack Daniels contest a couple years ago which was just a video so I really appreciate the feedback.


    Check out the updated version and let me know what you think....

    Thanks again!

    Radical Rick

    That is much better!

    Watch your camera angles, though, because we saw your thumb inside the cup (although your victim didn't)...