Bed of Nails – Table-Top Variation
The science behind the famous trick of lying down on a bed of nails!
You may have seen your favorite circus performers or magicians perform the classic Bed of Nails Trick… but what is the secret? Using a smaller version of the bed and a clear balloon, you can see the science behind the trick.
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- 2 boards - 9.5" x 4.5"
- 2 wooden dowels (1/2" thick, 10-12" long)
- 98 nails
- Clear balloons
- Adult supervision
- **Or you can get the kit!**
Start by preparing the bottom board by pre-drilling for the 98 nails that will be pushed through for the demonstration. Then to each end, pre-drill for the dowels that will be used to align the upper board.
Drill similar holes in the ends of the top board to allow for the board to slide freely up and down on the dowels.
Once your contraption is complete, insert one of the nails.
Blow up one of the clear balloons and press it into the single nail to pop the balloon. This is the perfect demonstration to your audience that this is an ordinary balloon and the nails are sharp!
Fill out the rest of your nail bed by inserting the remaining 97 nails into the board.
Now, blow up another balloon and place it on the bed of nails.
Put the top board in place so it slides down the dowels and start pushing down on the balloon. You can push pretty hard on the balloon before it ever pops… your audience won’t believe their eyes!
At some point the balloon will not be able to take any more pressure and will pop when you push hard enough… that’s okay, it shows your audience that you weren’t doing anything tricky!
How Does It Work
When you pop the first balloon with the nail, all of the pressure is concentrated on one point of the balloon so the balloon easily pops. When you place the balloon on the bed of nails, the pressure points are spread all across the surface of the balloon.
Just like the balloon, when a person lies on a bed of nails, their body is evenly distributed across the surface of the nails. The only real danger of being punctured by a nail is if the performer doesn’t lie down or get up correctly and pressure points of the nails are concentrated on one area of the body. Now you know the circus secret!
Placing a balloon on a bed of nails is pretty cool, but it isn’t a science fair project. You can create a science fair project by identifying a variable, or something that changes, in this experiment. Let’s take a look at some of the variable options that might work:
- Try spacing the nails differently. How does the spacing of the nails affect how much pressure the balloon can take?
- Try different types or brands of balloons. Do some handle more pressure than others?
That’s just a couple of ideas, but you aren’t limited to those! Try coming up with different ideas of variables and give them a try. Remember, you can only change one thing at a time. If you are testing different types of balloons, make sure that the other factors are remaining the same.