Want to shake up a group of physicists? Just show them something that acts in an unexpected way. That's what led to the discovery of a physics principle called the Brazil nut effect. For some time, hungry physicists had noticed that when you shake a jar of mixed nuts, the big, dense Brazil nut moves to the top of the jar. (You'd think it would sink to the bottom.) Check it out by performing the experiment with some mixed nuts of your own, or try this colorful variation.
YOU WILL NEED:
•Marble
•An empty transparent plastic jar with a lid
•Cornmeal, salt, or sand (enough to fill the jar 1/2 to 2/3 full)
STEPS:
1. Put the marble in the jar. Add the cornmeal, salt, or sand.
2. Seal the jar, then shake it up and down. It may take a little time, but eventually the marble will rise to the top. You might even hear it pop against the lid before you spot it.
WHAT'S HAPPENING:
You'd expect something denser than cornmeal, salt, or sand to stay at the bottom of the jar. Instead, when you shake the jar, both the cornmeal and the marble move up and down, and a bit of the cornmeal fills the space below the marble before it can fall back to its original position. Once the marble reaches the top of the heap, it gets buffeted around and sometimes falls just below the surface. But keep shaking, and it will resurface.
Want to shake up a group of physicists? Just show them something that acts in an unexpected way. That's what led to the discovery of a physics principle called the Brazil nut effect. For some time, hungry physicists had noticed that when you shake a jar of mixed nuts, the big, dense Brazil nut moves to the top of the jar. (You'd think it would sink to the bottom.) Check it out by performing the experiment with some mixed nuts of your own, or try this colorful variation.
