Hi Hels,
It's radio waves.
Do you have some way at school of creating two continuous notes in the audible range, both the same frequency, and varying the pitch of one very slightly? Doing so will cause a throbbing sound called a beat frequency, created from the two sound waves interfering with each other.
If the two original notes were high enough frequency they would be inaudible, and the beat frequency would be fast enough to be a continuous note, which could be varied by varying the frequency of one of the high pitched notes.
A theremin creates two frequencies in the radio signal range, far too high to hear. Once of the signal generators is connected to the pitch antenna, and can be made to vary in frequency by coming close to it, in the same way that moving near a television or radio aerial can cause it to go out of tune (body capacitance.) The two signals are added together electronically (this is called heterodyning) to produce the beat frequency signal that you can hear.
The volume antenna is connected to a different part of the circuit to affect the volume rather than the frequency, but works by body capacitance just the same.
Gordon
PS Writing poetry to music was something I did at primary school. It was Holst's Planet Suite, but we were not told that until afterwards. (I wrote a poem called The Sea that won me a ten pound book token in a competition run by the Daily Mail that our teacher entered all the poems in.)
It's radio waves.
Do you have some way at school of creating two continuous notes in the audible range, both the same frequency, and varying the pitch of one very slightly? Doing so will cause a throbbing sound called a beat frequency, created from the two sound waves interfering with each other.
If the two original notes were high enough frequency they would be inaudible, and the beat frequency would be fast enough to be a continuous note, which could be varied by varying the frequency of one of the high pitched notes.
A theremin creates two frequencies in the radio signal range, far too high to hear. Once of the signal generators is connected to the pitch antenna, and can be made to vary in frequency by coming close to it, in the same way that moving near a television or radio aerial can cause it to go out of tune (body capacitance.) The two signals are added together electronically (this is called heterodyning) to produce the beat frequency signal that you can hear.
The volume antenna is connected to a different part of the circuit to affect the volume rather than the frequency, but works by body capacitance just the same.
Gordon
PS Writing poetry to music was something I did at primary school. It was Holst's Planet Suite, but we were not told that until afterwards. (I wrote a poem called The Sea that won me a ten pound book token in a competition run by the Daily Mail that our teacher entered all the poems in.)
