Standing waves can be generated with either (1) both ends fixed, (2) one end fixed and one end free, or (3) both ends free. You can use either your hand or the motorized drive; your hand possesses better feedback for small adjustments in frequency. A metronome is available upon request for comparing the frequencies of various harmonics, or you can time them using the classroom clock or computer.
• Ask students to make predictions before each configuration of the device. Will fixed ends, free ends, or one open and one free end have the longest wavelength fundamental?
A standing wave oscillates in time, but the peaks do not travel in space. A standing wave can be created in a mechanical medium of fixed length with an oscillation at that medium's natural frequency, or a multiple thereof.