Naked Science Forum

General Science => General Science => Topic started by: paul.fr on 28/09/2007 11:47:55

Title: floating ball in coffe maker
Post by: paul.fr on 28/09/2007 11:47:55
look at this kettle, i have something like that. http://www.wholelattelove.com/Cuisinart/grind_brew.cfm

you will notice from the description that "There is also an unusually wide water level indicator on the right side of the machine that is well marked and uses a red floating ball for maximum readability"

when the water is boiling, the red floating ball drops to the bottom of the water indicator channel. why does it do that?
Title: floating ball in coffe maker
Post by: Karen W. on 28/09/2007 12:40:27
Because you are loosing water, and the ball shows you that! Wouldn't the water level go down with the escape of steam and then the use of the water going into the pot and the water going from tank to pot surely would do that! Like a toilet float.. LOL Am I wrong or does this ball sink to the bottom before the water starts to dissipate?

Its just like a water level indicator right?
Title: floating ball in coffe maker
Post by: paul.fr on 28/09/2007 12:50:37
Quote from: Karen W. on 28/09/2007 12:40:27
Because you are loosing water, and the ball shows you that!

No, the ball sinks to the very bottom, then seconds later rises to the top again. it only does this at boiling point.
Title: floating ball in coffe maker
Post by: Karen W. on 28/09/2007 12:55:42
Oh That is odd! I wonder why! Dumplings in chicken and dumplings do that to. At first you put them in then boiling begins again and they sink then after a moment they pop back up and float on top again. I do not get it!
Title: floating ball in coffe maker
Post by: rosy on 28/09/2007 14:09:11
Because bubbles form in the water.
Water with bubbles in is less dense (weighs less per mL) and so it is more likely that the ball will be more dense and so will sink through the bubble-y water.
In the kettle situation it's complicated a bit since the ball is often smaller than the bubbles. What's happening then is that a bubble rises up under the ball, bursts leaving the bubble resting on air rather than water (which won't support it) and so falls until it finds the water lower down the guage and starts to float on that. The level of the water then rises up to be level with the rest of the water in the kettle until another bubble bursts.
Make sense? I might find time over the weekend to draw a picture, but more likely not as I'm pretty busy...
Title: floating ball in coffe maker
Post by: Karen W. on 28/09/2007 14:22:52
That is a good explanation and I think I actually understand what you mean.. thanks Rosy..
Title: floating ball in coffe maker
Post by: neilep on 28/09/2007 14:58:30
Nice Kettle !!

Whack it on !!...I'll be over soon !!
Title: floating ball in coffe maker
Post by: paul.fr on 28/09/2007 21:42:17
Rosy, you are my hero..or heroine, but heroine does not sound as good as hero.
Title: floating ball in coffe maker
Post by: Karen W. on 01/10/2007 05:47:57
Quote from: paul.fr on 28/09/2007 21:42:17
Rosy, you are my hero..or heroine, but heroine does not sound as good as hero.

LOL NO It sounds BETTER!!!!! LOL!
Title: floating ball in coffe maker
Post by: ukmicky on 01/10/2007 21:42:24
The rising bubbles thingy is the same reason they believe planes crash and ships tend to sink in the burmuda triangle, however rather than air in the Triangle its rising bubbles of Methane
Title: floating ball in coffe maker
Post by: neilep on 01/10/2007 22:19:42
Quote from: ukmicky on 01/10/2007 21:42:24
The rising bubbles thingy is the same reason they believe planes crash and ships tend to sink in the burmuda triangle, however rather than air in the Triangle its rising bubbles of Methane

yes, yes..I posted a question about that very phenomena !!..I am awaiting my bath in February to test it !

http://www.thenakedscientists.com/forum/index.php?topic=9740.0