ALTOONA, Pa. (WTAJ) — In this episode of Science with Shields, Christy Shields plays a game of will it sink or float to explain density.  

What you need:  

  1. Aluminum foil 
  2. Scissors 
  3. Water 
  4. Glass bowl 


Fill your bowl up with water. Next, cut your aluminium foil into little squares. Stick a piece of foil into the water. Notice how it sinks to the bottom. With your hand take a second piece of foil and crumple it up into a ball. Stick it in the water, notice how this one floats and does not sink to the bottom no matter how hard you try. Now, with the flat piece of foil at the bottom of the water, crumple it into a ball in the water. Notice how this one does not float back to the top and is still sunk.

Get daily updates on local news, weather and sports by signing up for the WTAJ Newsletter


This is a fun game and also explains density. Density is mass over volume. It is used to measure how heavy something is compared to its size. If something is less dense than water, it floats. If it is denser than water it sinks. Why the second piece of foil floats and does not sink is because when we crumple it into a ball, it now has air pockets in it. These air pockets reduce the foil’s average density, making it float. The one we crumple under the water, because it is in water will not get any air pockets in it which is why it stays more dense and continues to be sunk. Try this out with different objects and let us know how it goes!