What to do:
Collect 8 plastic drinking straws. If they are the bendy type, cut off the bend and use the straight part of the straw. The first straw will need no cutting. Cut about 2 cm off the end of the next straw, 4 cm off the third straw, 6 cm off the fourth straw and so on until all 7 straws have been cut. Lay a piece of clear tape on the table, sticky side up, and arrange the straws on the tape from longest to shortest, with the tops of the straws all lined up with each other. Wrap more tape around the straws to secure them together. Blow over the top of the straws.
Which straw makes the highest pitch noise? Which straw makes the lowest pitch noise? Why do you think this is?
What is happening?
The pitch of a sound corresponds to the frequency of the sound wave: the higher the frequency, the higher the pitch. The shorter the straw, the higher the frequency of the sound wave and the higher the pitch. The longer the straw, the longer the frequency of the sound wave and the lower the pitch. To find out more about pitch, click here and watch this video.