3D40.20 Singing Rod
Longitudinal standing waves in an aluminum rod, resonance
An aluminum rod is held at various nodal points and stroked with rosined fingers or gloves, producing a loud sound that lasts a long time. The sound can be amplified by touching the end of the rod to a styrofoam cup.
-  Aluminum rod
-  Rosined gloves
-  Bag of rosin powder
-  Solid resin
-  Styrofoam cup
- This demonstration requires a lot of advance practice.
- Wear rosined gloves and add more rosin powder as necessary.
- Pinch the rod between two fingers at the L/2 location.
- Stroke the rod firmly starting at L/2 all the way to the rod's end. The rod produces the first harmonic.
- Press the end of the rod to a styrofoam cup after it has been excited to amplify the sound.
- Repeat step 2 to 4 while pinching the rod at the L/4 and then L/6 positions to produce the second and third harmonic respectively.
- PIRA 3D40.20
- Don't attempt this at home!
If you have any questions about the demos or notes you would like to add to this page, contact Ricky Chu at ricky_chu AT sfu DOT ca.