The Traveling Marble
 

In this experiment you will use physics to make a marble travel to the top of a jar of salt (or sand). This is an example of the physics principle called the Brazil nut effect.


Supplies needed:

  • An empty transparent plastic jar with a lid - old peanut butter jars work great!
  • Enough salt or clean play-sand to fill the jar 2/3 full.
  • Marble

Procedure:

  1. Put the marble in the bottom of the jar.
  2. Add the salt or sand – fill the jar 2/3rds of the way full.
  3. Seal the jar.
  4. Shake the jar up and down over and over again.
  5. It may take a little bit of time, but eventually the marble will rise to the top.Most people think the marble will stay at the bottom because it is denser. Instead, when you shake the jar, both the salt (or sand) and the marble move up and down together. Each time this happens a small amount of the salt (or sand) fills the space under the marble before it can fall back to its original position. This keeps happening until the marble gets to the top.

Skills: Observing, inferring, predicting, communicating, formulating hypotheses, identifying and controlling variables, experimenting