A whistle with a sliding piston is used to demonstrate differences in frequencies. When the piston is extended all the way, the frequency and pitch of the whistle is lowered. If the whistle is blown with the piston closed, the frequency and pitch will be higher.
Set up time
No setup required.
Physics and Science Concepts
Waves, Oscillations, Frequency, Pitch
First, slide blow into the mouthpiece located at the top of the whistle. Next, move the piston to create different frequencies. If you have trouble moving the piston and blowing into the whistle simultaneously, have another person work the piston.
Do not blow too hard or for extended periods of time as this may cause dizziness or headaches. Clean the mouthpiece in between use.