Try this simple physics experiment using LEGO Bricks and sand in your backyard
Children are students of the world. As they explore, they become fascinated by the results they expect least. Here’s a quick little physics experiment that we came across on a blog called Kid Minds that will play with these expectations. Just head outside to the sandbox with a handful of LEGO Bricks and a bucket.
Scoop a few shovelfuls of sand into the bucket, and sprinkle some LEGO Bricks of various sizes on top. Then cover completely with another layer of sand.
Ask your kids to predict what will happen to the LEGO Bricks when you shake the bucket. Will they settle to the bottom because they’re larger than the sand grains? Or will they get mixed around the sand?
When you start shaking the bucket back and forth, watch what happens. One by one, the LEGO Bricks will start to emerge at the top. They’ll pop out and stay there, no matter how long you shake. You can repeat the experiment with different objects. Try denser, heavier ones such as stones or marbles and see what happens.
What’s happening?
If you have preschoolers, don’t be surprised if they play with this experiment for a long time! For your grade-school kids, there’s a physics lesson and some daily application.
When small particles, like sand or grains, are shaken, they circulate around their container in a specific pattern. If you were to watch a video of this in motion, you could see the particles move up through the center of the container and then make their way back down the sides. This is called granular convection. During the shaking, those little sand grains just fall easily into the empty spaces created by the motion. At the same time, this motion is almost like a tide that carries a larger object right to the top!
Where else can we find this?
As it turns out, scientists have a name for what happens when larger objects rise to the top as smaller ones sort to the bottom: the Brazil Nut Effect. If you’ve ever opened a can of mixed nuts, you’ve probably found those larger nuggets right on top, while peanuts have, weirdly enough, settled to the bottom. It’s only the physics of jostling at work!
This happens with breakfast cereal, too. The bottom of the bag is nothing but broken bits and crumbs. No yummy bits of dried fruit or nut clusters.
However, knowing this will make your movie night easier. Just shake the bowl of popcorn from time to time so the kernels fall to the bottom!
In the larger world, it’s easy to see how this jostling is a problem that food manufacturers would love to solve. On the flip side, manufacturers can use the power of granular convection to prepare other materials. What are some of the possibilities? One answer might be right in your sandbox!