Theremin

This simulation recreates the idea of a theremin, an instrument played without touching it. Students press and drag over a plane: left to right sets the pitch across four octaves, and up and down sets the volume. Ring shapes draw the electric field around the antennas. Readouts show the frequency, the nearest note, the volume and the wavelength in air. Options let students choose a waveform, snap pitch to equal-tempered notes or keep the sound playing while they move the pointer. It helps students link position to frequency, understand that equal distances give equal musical intervals and connect pitch to wavelength.

• Drag slowly from the left edge to the right edge and watch the Frequency readout rise.
• Move up and down at a fixed position and notice that only the Volume changes.
• Turn on Snap to notes and glide across the plane to hear the pitch jump between notes.
• Tick Keep playing so you can change pitch just by moving the pointer, no pressing.
• Switch Waveform from sine to sawtooth and compare the tone at the same frequency.

1. 1Connect the position of the pointer with the frequency and volume of a sound.
2. 2Explain that equal steps in distance can give equal musical intervals.
3. 3Compare the sound of sine, triangle, square and sawtooth waveforms.
4. 4Calculate how wavelength shrinks as frequency rises.

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