A water xylophone is an entertaining and musical experiment that has lasted the test of time.
After all, making music is always a great pastime, especially when you can make your own experiment and learn about STEM principles while doing it!
Read on to learn how to create your own water xylophone to help teach kids about sound while unleashing their inner musician at the same time!
Materials
- 5-7 identical glass cups or jars
- Food colouring (different colour for every glass)
- Water
- Metal utensil
- Wooden spoon or chopsticks
- Hard plastic reusable straws or plastic utensil
How to Create a Water Xylophone
Step 1
Line up your glasses or jars side by side. They should be close together but don’t have them touching.
Step 2
Fill up the first glass about ¾ full.
Step 3
Fill up the glass next to it just a little less than the one before. Continue this process with the remaining jars, add less water to each jar in sequence.
Step 4
Add a few drops of food colouring to each glass. Use a different colour in each to replicate a xylophone!
STEM Q for You: Before you tap the metal utensil, wooden spoon, and plastic straw on each glass, make a prediction of what you think will happen. What sound will be produced with each material? Will it vary from each glass?
Step 5
Take the plastic straw and tap it against each glass.
STEM Q for You: What kind of sound is produced? … Depending on the density of straw, there will likely not be much sound or if there is sound produced, it will be dull and quiet.
Step 6
Take the wooden spoon and tap it against each glass.
STEM Q for You: What kind of sound is produced? How is it different from the plastic straw? … The wooden spoon likely won’t produce a loud sound either. It will sound dull and quiet too!
Step 7
Take the metal utensil and tap it against each glass.
STEM Q for You: What kind of sound is produced? How is it different from the other utensils? … The metal utensil will produce a “chime” or ringing sound against the glass jar. Each glass will produce a different pitch when tapped.
STEM Q for You: Which material of utensil created the best sound? Why do you think this is?
Step 8
Time to put you music skills to the test! Try to recreate some of your favourite songs or make a new one!
Try this! Add or dump out some of the water in each glass. Playing around with the water levels will change up the sound that is produced! You can also try tapping different places on the glass to experiment with different pitches.
What is Pitch?
Sound is created by vibrations called “sound waves” which travel at different speeds. The speeds at which the sound waves travel are called frequencies.
Pitch describes the frequency of a sound wave. Something that is high pitched means that the sound waves are vibrating very fast whereas something that is low pitched means that the sound waves are vibrating very slow.
In the water xylophone you may have noticed that when there is more water, the pitch is lower! Glasses with less water have higher pitches.
Why Does Pitch Change with Each Glass?
Sound waves are vibrations that travel through a medium (in this case water) that creates sound. The different levels of water in each glass determine how the sound waves will vibrate.
Sounds waves travel quicker in small amounts of water because they can vibrate faster, thus producing a higher pitch.
With larger amounts of water, the sound waves are longer so they produce a deeper sound!
