Impossible Forks
For this trick, just push the forks together so the prongs intersect, then poke a toothpick between the prongs. (This might take a few tries!) With a little practice, you should be able to balance this easily on a finger. And, with a little practice, you can even get the whole structure to balance on another toothpick.
This isn’t just a way to pass the time at a restaurant — it’s also a great example of the center of mass, or the point where an object is balanced. For an even simpler demonstration of center of mass, grab that butter knife from your boring restaurant place setting. Rest it on top of your index fingers, one on each end, and slowly slide your fingers together (without tipping the knife over!). The point where your fingers meet is the center of mass.
No-Spill Bottle
For this trick, you need a bottle or cup with a bunch of holes, some water, and room to make a splash! With a slo-mo shot (or quick eyes), you’ll see that as long as the bottle is falling, the leak stops. That’s because gravity pulls everything down at the same rate, called the acceleration of gravity. While the bottle is falling, the water can’t leak because, if it did, it would be falling faster than the bottle is.
Antigravity Slinky
This trick is our favorite, but capturing this in slow motion is a must! On video, you can clearly see the bottle of the slinky stay still while the coils above it collapse and fall. Plus, the slowed-down sound of the coils clinking together is incredibly satisfying!
Here’s what’s going on. Gravity is stretching the slinky out, but the tension in the coils is also pulling the slinky in. (Tension is the force of each coil trying to get the slinky back to its normal shape.) When you let go, tension and gravity cancel each other out, and the bottom of the slinky doesn’t move.
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