Science

[groovy chick]

Why does a bottle that is almost full of water produce a high note when you blow over it?

[rojash]

Whe you blow across the top, you cause the air in the bottle to vibrate at its resonant frequency. The smaller the volume, the shorter the wavelength, and hence the higher the frequency.

This is similar to but not the same as what happens when you run your finger round the top of a glass. In this case it is the glass itself that resonates. The wavelength (and hence the frequency) will depend on the area of glass that is not prevented from vibrating by the damping effect of the water.

[Thunderchild]

yes that is about it frequenzy (high or low note) is inversly proportional to wavelenght that is proportional to the length, volume size ecc. if you see what i mean