I've always wondered about this....

When I turn on the hot water, cold water comes out at first, then the hot
water gets to the faucet after a bit. When the hot water arrives, the faucet
makes a different sound!

Why is this?

On Feb 22, 12:48 pm, "Bill" wrote:
I've always wondered about this....

When I turn on the hot water, cold water comes out at first, then the hot
water gets to the faucet after a bit. When the hot water arrives, the faucet
makes a different sound!

Why is this?

Me too. I notice this on the valve for the bathtub (which is one of
those anti scalding valves).

"Bill" wrote in message
...
I've always wondered about this....

When I turn on the hot water, cold water comes out at first, then the hot
water gets to the faucet after a bit. When the hot water arrives, the
faucet makes a different sound!

Why is this?

The cold is right there but the hot has to come from the heater and the
travel time is what you are noticing.

Hot water is less dense and experiences a different turbulence (and sound)
as it passes through the valve mechanism.

On Feb 22, 6:46 pm, "Charles Schuler"
wrote:
"Bill" wrote in message

...

I've always wondered about this....

When I turn on the hot water, cold water comes out at first, then the hot
water gets to the faucet after a bit. When the hot water arrives, the
faucet makes a different sound!

Why is this?

The cold is right there but the hot has to come from the heater and the
travel time is what you are noticing.

Hot water is less dense and experiences a different turbulence (and sound)
as it passes through the valve mechanism.


And, as the water de-pressurizes gases come out of solution and form
new bubbles.

Water holds more dissolved gases when cold, but the gases stay in
solution in the water heater because of the pressure.
The water gets to the valve, the pressure goes down dramatically, and
the gases come out of solution.

This is the same mechanism that causes bubbles to form at the bottom
of a pot of water on the stove long before its boiling.

Dave

And, as the water de-pressurizes gases come out of solution and form
new bubbles.

Water holds more dissolved gases when cold, but the gases stay in
solution in the water heater because of the pressure.
The water gets to the valve, the pressure goes down dramatically, and
the gases come out of solution.

This is the same mechanism that causes bubbles to form at the bottom
of a pot of water on the stove long before its boiling.

True, Dave ... thanks for the addition.

wrote:
On Feb 22, 6:46 pm, "Charles Schuler"
wrote:
"Bill" wrote in message

...

I've always wondered about this....
When I turn on the hot water, cold water comes out at first, then the hot
water gets to the faucet after a bit. When the hot water arrives, the
faucet makes a different sound!
Why is this?
The cold is right there but the hot has to come from the heater and the
travel time is what you are noticing.

Hot water is less dense and experiences a different turbulence (and sound)
as it passes through the valve mechanism.


And, as the water de-pressurizes gases come out of solution and form
new bubbles.

Water holds more dissolved gases when cold, but the gases stay in
solution in the water heater because of the pressure.
The water gets to the valve, the pressure goes down dramatically, and
the gases come out of solution.

This is the same mechanism that causes bubbles to form at the bottom
of a pot of water on the stove long before its boiling.

Dave


Gee I just learned stuff about something I never even thought about:-))

Lou

On Thu, 22 Feb 2007 09:48:22 -0800, "Bill"
wrote:

I've always wondered about this....

When I turn on the hot water, cold water comes out at first, then the hot
water gets to the faucet after a bit. When the hot water arrives, the faucet
makes a different sound!

Why is this?



Hot water moves much faster than cold water. It's similar to blowing
through a tube; blow harder and the sound changes.

Take a plastic jug and put a small hole near the bottom. Fill it with
hot water and note the stream. Do the same with cold water. It is
amazing to see the difference. You can record the time it takes to
empty for comparison. There is more (kinetic) energy in the warmer
water.

Phisherman wrote:
On Thu, 22 Feb 2007 09:48:22 -0800, "Bill"
wrote:

I've always wondered about this....

When I turn on the hot water, cold water comes out at first, then the hot
water gets to the faucet after a bit. When the hot water arrives, the faucet
makes a different sound!

Why is this?



Hot water moves much faster than cold water. It's similar to blowing
through a tube; blow harder and the sound changes.

Take a plastic jug and put a small hole near the bottom. Fill it with
hot water and note the stream. Do the same with cold water. It is
amazing to see the difference. You can record the time it takes to
empty for comparison. There is more (kinetic) energy in the warmer
water.

I am going to try that:-))

Lou