Exploring sound with a water xylophone

This was a project with my 4 year old. I wanted to give her something to do, so I helped her set up a water xylophone.

Materials –

Empty glass bottles or glasses
Food coloring (red, blue, yellow)
Spoon (wooden or metal)

Recycle empty glass bottles that previously held frappucinos from a popular coffee brand or use 6 of the same type of water or wine glasses. I chose the beverage bottle because they were thicker walled and less prone to breakage (but note they don’t sound as pretty as thinner walled glasses).

Fill the bottles with water to gradually increasing levels and add food coloring. I thought making a rainbow would serve another purpose – it was a fun color mixing activity as well.



Next take the spoon (we used a wooden one for safety reasons) and experiment with the water xylophone.

Hitting the glass on the side made one kind of sound.


Hitting the glass on the top with the flat side of the spoon produced another kind of sound.


Each glass sounded differently based on how much water was in the glass. The bottles with less water sounded higher in pitch than the bottles with more water in them. The reason is that the more water in the glass, the less the glass is able to vibrate and therefore it produces a lower sound.

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