three jars with different water levels

Discover Pitch With a Water Xylophone

While You Play

As you and your child fill and color your bottles, discuss the concept of pitch. Explain that pitch is how high or low a note sounds. Sing a song together and point out the high notes and the low notes. Make predictions about which bottle will make the highest sound and which bottle will make the lowest.

What You'll Need

  • Glass bottles or mason jars (make sure all jars are the same size and volume)
  • Water
  • Wooden spoon or stick (something to hit the bottles)
  • Optional: Food coloring (to make the colors of the rainbow)


  1. Fill six bottles with different levels of water. Start with ¼ cup water and add ¼ cup more water as you scale up. The least-filled bottle should contain ¼ cup water, the next bottle should have ½ cup, then ¾ cup, etc. until all the bottles have water. Optional: add food coloring to each bottle to make the colors of the rainbow.
  2. Use the wooden spoon to tap the glass bottles to make noise. Were your predictions about pitch right?
  3. Now experiment! Does the sound change if you hit the top or the bottom of the glass? How about if you use a different tool to hit the glass? What happens if you use juice or milk instead of water? Don’t forget to drink the juice or milk when you’re done with the experiment!

This activity comes to you from the creators of The Cat in the Hat Knows a Lot about That.

Iowa PBS STEAM Activities and Crafts provided by PBS KIDS Parents.