And I thought a bubble was a bubble!
skylight
Posts: 1,915
Having just watched a documentary about bubbles and their usefulness as a tool for scientists I was shocked at one point where a patient was having ultrasound and in order to enhance the pictures they injected air into the patients bloodstream!!
My immediate thought was "What about the bends?"
after the programme i did a bit of research and found that the medical industry has produced special types of microbubbles that cannot coalesce and produce a potentially dangerous larger bubble.
Fascinating stuff.
http://depts.washington.edu/fluidlab/theses/cethesis.pdf
My immediate thought was "What about the bends?"
after the programme i did a bit of research and found that the medical industry has produced special types of microbubbles that cannot coalesce and produce a potentially dangerous larger bubble.
Fascinating stuff.
http://depts.washington.edu/fluidlab/theses/cethesis.pdf
Comments
On the medical side if you read the thesis in the #1 post The bubbles can be vibrated with ultrasound to help break up blood clots, a similar idea was used in the documentary to make a water spout change from just plain water to an ultrasound bubble filled spout that could clean,
It could mean the end of needing hot water for cleaning, saving energy bills.
Ah Guiness, I love the creamy foam the nitrogen bubbles produce, and the slightly tart pucker from soured Guiness that they pasteurize and add back into the brew.
Yes that is his name. Wonderful Belfast accent as well.
1) A round of beers and a packet of salted peanuts is bought for two or more guys. Make that nice lively beer but not too lively.
2) Each guy drops three of the salted peanuts into his beer.
3) The peanuts sink to the bottom initially.
4) Slowly bubbles nucleate and grow on the peanuts and they will lift the peanuts up to the top of the beer.
5) On reaching the surface the bubbles detach from the peanuts which then sink back down to the bottom.
6) We are back to 4) again so this whole process repeats many times, peanuts migrating magically up and down in the beer. This is a "beer engine".
The game is then that the guy whose "beer engine" stops first has to buy the next round.
Whist this was an interesting game to play once or twice sadly it did not catch on. Probably because in involves a lot of time watching your beers rather than actually drinking them:)
A slightly more advanced version of the game that gets you to drinking the beer quicker is "beer engine racing" where you time the migrations of the peanuts and the guy with the slowest one buys the next round. But that involves the complication of timing and the ensuing arguments over the results.
I was quite taken with my, admittedly accidental, discovery of the "beer engine". I suspect the salt on the peanuts is important for it's operation, stimulating the nucleation.
Not sure if it works with unsalted. This calls for further ...err...research. I'll be back in a bit...
Edit: See here for some nice examples of bubble nucleation and theory: http://en.wikipedia.org/wiki/Nucleation
Nice interesting article thanks
Remember the 'Soda and Candy' fountain trick?
Mythbusters did an episode on that, and found that salt had a lot of 'nucleation sites'...