I am just going to apologise now for this one; “I am very sorry if the noise of this drives you nuts (but it is totally worth it)”. If there is one thing that all children love it is things that make noises, be it banging pots together or one of those V Tech toys that sings at you. Well this activity plays right into that love of making noise, saying that this is also makes a terrific experiment to demonstrate how sound works.
There are two different ways to make these harmonicas, both produce similar sounds, but one is slightly easier for smaller children. Just as a warning please be careful about splinters, this is not like a traditional harmonica were you can run your mouth along it. Also take care about using coloured craft sticks with smaller children, as the colour tends to run once they get wet, the best way to play them is by pulling your lips over your teeth and placing the harmonica on the skin just under your lips (which should be over your teeth if you pull your lips in).
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You will need:
- Craft sticks – we used both thick and thin craft sticks
- Elastic bands – ideally the thicker the band the better.
- Loom bands – hurray you can finally find a use for all those discarded bands that you have lying around.
Technique one – better suited to smaller children.
- Take one of your craft sticks and put an elastic band around it (length ways)
- Cut the straw into 2 pieces so that they are the width of the craft stick.
- Put the straws under the elastic band, one at either end.
- Put the other craft stick on top and use the loom bands to keep everything in place by wrapping them around each end.
- Cut out a piece of paper so that it is the same length and width as your craft stick.
- Place the paper onto one of the craft sticks.
- Place the other craft stick on top and wrap one loom band around an end.
- Cut your toothpick to the width of the craft stick.
- Put your cut toothpick between one of the craft sticks and the piece of paper, run it down until it is next to the loom band and then push it in so that none of it is sticking out.
- Put the other toothpick in the same position at the other end and then finally wrap the final loom band around the other end.
The science behind it
When you blow into the harmonica you are causing the paper or elastic band to vibrate. These vibrations need a medium like air in order to travel and produce the sound that reaches are ears. The frequency of this vibration is called the Hertz. The quicker it vibrates, the higher the pitch with be. If you squeeze the two sides of the harmonica together it will change the pitch of the noise produce.
With older children you ask them to experiment with this by asking them what would happen it you changed the width of the paper or elastic band. Would it make a higher or lower pitched sound? As it happens we did this activity with my little ones’ cousins, who are a few years older. They tried this and found that the thinner the paper, the higher the pitch was. They then took it further and made one with a piece of paper that went from being wide at one end to thinner, by doing this they actually managed to produce different pitches using the same harmonica. EC saw what his cousins were doing and had a go himself. He didn’t manage to produce one that was as effective as his cousin’s harmonica, but he was at least trying to experiment.
This activity may help development of:
Fine motor skills
Understanding of how sound works
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