Curious about sound...

This is totally a non-important question; just curious...

When I open only the hot water side of any of my faucets, the sound of the water exiting the faucet changes when the water gets warm (it is only a matter of seconds from first turning the faucet on until water gets warm, probably 20' of 1/2" copper from heater to faucet).

If I had to describe it, it sounds like the "pitch" of the noise of running water changes.

If this is happening, and I'm not imagining it, why/what is happening?

Thanks!
Jim

If there are bib washers in that faucet, try changing them..

water

Hot water has a lower mass than cold water which changes the pitch, just as the sound of air coming from a pipe will change when the lighter natural gas arrives at the valve.

another change in noise

i notice the same thing, as well as a second noise.

Some kitchen faucets, when hot water reaches them, create a high pitch ("whistle") too, above the base noise. This overtone noise can be heard 30' away -- it carries farther than the base noise, which the person running the water can barely detect above the base noise.

Running hot water can cause irritation at a distance.

david

Thanks!

I suspected it had to do with the mass/density of the water, but wasn't at all sure I was right.

Thanks, all, for the responses.

Jim S.