Membranophone

Curriculum links:

• Physics – Forces, energy and sound – Explore how sound travels through materials

Learning objectives:

1. Explore sound and harmonics
2. Design and construct your own musical instrument
3. Explore the different properties of materials

Materials:

• Plastic bottle (500ml)
• Rubber/latex glove or balloon  
• Elastic band
• Sheet of card
• Scissors
• Straw
• Tape

Safety:

• When cutting the bottle, be careful as the plastic edges can be sharp.

Instructions:

• Cut the bottle in half using scissors, get help from an adult doing this.
• Take the top half of the bottle and poke a straw-sized hole on the side of the bottle near its mouth. Put the straw through the hole to test it for size.
• If using a glove, cut the palm out of the glove, or if using a balloon, cut the end off the balloon- this is your membrane. Stretch it over the cut end of the bottle and secure it with the rubber band.
• Roll a piece of card into a tube, making it as tight and straight as possible. Place the paper tube in the mouth of the bottle and let go of the paper tube when it barely touches the membrane. It should fit securely in the bottle opening.
• To play your new membranophone, blow into the straw. If you don’t hear anything try adjusting the tension of the membrane and make sure the chamber inside the bottle is sealed. You can use tape to close any gaps around the straw or the paper tube.

How it works:

Sound is made up of vibrations. These are called sound waves and they are what we hear. These sound waves are formed by objects shaking back and forth. They travel through air, water, and solid objects as vibrations. When they reach our ears, these waves make our eardrums vibrate. This sends signals to the brain and it figures out what we’re listening to.

Membranophones are musical instruments that make sound from the vibrations of stretched materials. Drums are a good example of a membranophone.

This experiment which was originally put together by Exploratium in San Francisco was brought to Ireland as part of the European Tinkering project. The idea of this project is that you build your own devices / inventions and then you keep messing with them in order to make new things. For the membranophone Tinkering might mean changing the length of the straw or tube, poking holes into the tube at different lengths (like with a recorder or tin whistle instrument) or even trying different materials entirely. Once you are producing vibrations you will be producing sound. Changing the types of materials or the length of things will change the shape of the vibrations produced and therefore change the sounds. For instance, if you shorten the pipe, the higher the pitch of the sound. You should muck about with you constructions and see what new inventions you can come up with.