100 Days Project

Nanogirl: Star Science

Nanogirl wants to find 100 friends to do science experiments with her to prove that no matter who you are or what your education level, you can always have fun with science.

Day 32:

Straw duck mimicking device

Today was a very exciting day for Nanogirl as she got to meet a scientist who she has been a fan of for many years. 

Dr Chris Smith is a clinical virologist and also the founder and presenter of the amazing podcast The Naked Scientists.

He helped me to make a duck sound mimicking device using just a straw, a pair of scissors and some serious lung power.

We flattened one end of the straw at the tip, then cut both sides at an equal angle so that it turned it into a pointy end instead of a flat end.  Making sure that the end you cut is squashed flat (you may need to gently slide your teeth together on it to ensure a good crease), place the pointy end in your mouth and blow really hard into the straw.

If you blow it correctly, and you may need to try blowing harder or softer and with more or less of the straw touching your lips, you should hear a sound produced that is a bit like a duck quack.

The science behind this is vibration, we have already seen this on day30 when we ran our finger across the top of a glass.

When you blow into the end of the straw, the two pointy pieces of the tip that you cut vibrate together. The vibration travels down the straw, and reflects from the end setting up a wave in the air inside the straw.  This vibration then bounces from the top to the bottom of the two ends of the straw and so what you hear is actually the vibration moving up and down.

It will take more time for the vibration to travel all the way from the top to the bottom of a longer straw which will result in a lower pitch than a shorter straw which will give a higher pitch.  You can test this by listening to how the sound changes as you make the straw shorter by cutting off strips from the flat end.