[dentstudent (OP)]

Have you seen it? I've seen some little water features (is Charlie Dimmock still around) in DIY stores and they have some smokey layer on the surface of the water. What is it and how is this formed?

[DoctorBeaver]

It's the goldfish having a crafty ciggy

[dentstudent (OP)]

Smoked haddock?

[dentstudent (OP)]

Clearly its Ian GILLan, Ian Plaice and Jon "Dory" Lord doing their most famous track!

[Soul Surfer]

I know what you mean, its a bit like the fog you get from dry ice and water although I don't think that can be the way its done.  Looking at it it appears to be fine droplets of water or steam.  my guess is that the drive for the fountain is not a pump but a very hot wire that briefly boils a bit of water to work the pump like a coffee percolator this also sucks some air through the mixture but it leaves a bit of cool steam in the air to float on the water.

[dentstudent (OP)]

But wouldn't this make a noise too? The ones I've seem to be relatively quiet. And it really hugs the water surface too, which might not be the case for steam? Warmer bodies tend to rise, and this "smoke" certainly doesn't.

[Soul Surfer]

After a bit of thought I tend to agree with you and wondered if it could be a process that atomises water droplets this could be a very powerful spray or possibly untrasonic cavitiation of the water surface.

  If you Google  +mist +fountain + water

You will see that they use ultrasonics to force fine droplets off the surface of the water.

[dentstudent (OP)]

Thanks Ian! I'll go and have a peek......

Does it have any industrial use or is it purely for aesthetics? there must be a need somewhere for chasing water particles from the surface.

[dentstudent (OP)]

OK, I've ssen the link, and understand that it is ultrasonics. But how? Is it a bit like the kitchen science experiemnt from a couple of weeks ago, with the styrofoam cup, the carpet and water? Where waves peaks collided, a mini fountain was formed. Do the ultrasonic waves work in the same way?

[Soul Surfer]

The ultrasonic waves cause violent movement of the surface of the water so that small droplets of water are shaken from the top of the waves that form.

[dentstudent (OP)]

Thanks SS! I think that's all clear now!

[daveshorts]

I think it is similar to the kitchen science experiment yes

[Chartreuxe]

Have you seen it? I've seen some little water features (is Charlie Dimmock still around) in DIY stores and they have some smokey layer on the surface of the water. What is it and how is this formed?

Dry ice is added to the water feature to create the mist.  It's CO2 from the frozen CO2 in the water.  Observe that the 'mist' appears above the water reservoirs.

[rami999]

i dont know what are you talking about