What you Need
What to do
Add 3-4 tsp of salt into the wash bottle, or rather more into a washing up liquid bottle and then top it up with water.
Add some washing up liquid into the tank of water - probably 2-3 times stronger than the washing up water.
Clear any bubbles from the top of the tank.
Drip water onto the top of the tank from 5-10cm above and look at the bubbles being formed on the surface. Are they all the same?
Now do the same thing looking into the side of the tank, for a couple of hundred drops, does anything interesting appear?
What may happen
On the top mostly you will produce normal drops, but sometimes you will see what look like bubbles but if you look closer they reflect light much better and they have far more momentum skittering across the surface.
If you look from the side you sometimes see bubbles which actually sink rather than float.
This video is slowed down by 10x
Why does it happen?
You are creating what are known as antibubbles. A conventional bubble is air surrounded by a thin film of water in air, an antibubble is the other way around, water surrounded by a thin film of air in water.
Both types of bubble are highly unstable in pure water because water molecules attract one another very strongly and try to minimise the surface area of the liquid. Detergent molecules have one end which is very attracted to water and a long oily tail which is repelled by it. so they cover the surface of the bubble stabilising it.
The air in an antibubble will cause it to float gently so they would be hard to tell from conventional bubbles. The salt weighs them down so they sink and you can tell the difference.
The antibubbles seem to form best when they are dropped onto water that is falling so the impact is less violent.
Ahhh, I like this one, Dave.
Yes it would certainly make them more visible, I quite like the pure and simple as you can see what is going on better...
That is very interesting did you come up with that? archie bishop, Wed, 1st Apr 2009
Actually I met some irish schoolchildren making them in a science competition in Dublin 4 or 5 years ago. Although I was aware of the skittering antibubbles on the surface for a lot longer than that. daveshorts, Tue, 14th Apr 2009
Yo yo, this is da bomb, literally Marono, Fri, 24th Apr 2009
that's wicked! ginge, Sun, 3rd May 2009
That's pretty neat... Mystery person, Sun, 25th Oct 2009
this science projects sucks brittany, Tue, 3rd Nov 2009
WHATS your inspiration to do this "antibubbles"? mama1, Fri, 5th Feb 2010
Hello....I likes this Site.. kindof... buht i need more info on Anitbubbles and this site did not provide me with that........ um.....and the videos did not show a clear picture of antibubbless NUN OF UR BUISNESS, Sat, 6th Mar 2010
omg @ the last comment! Well I bet the creators are very sorry and will come grovelling to you with compensation because after all they WERE trying to write a droll, detailed scientific paper rather than making a fun website! Why don't you make them yourself if you can't see them on the video... which is very clear to me? Nessa, Tue, 30th Mar 2010
I agree with brittany.. this science project sucks.. it doesnt work and it gets boring.. if your gona be lazy when picking a project at least pick one that is better than this one. hailey, Wed, 14th Apr 2010
Thanks! I'll be using this as a transition activity between "the chemistry of life" and "Cells" I hope it help students have a more meaningful understanding of what a membrane is. Sci Teacher, Thu, 9th Sep 2010
omg this is awewsome thank youcfor making this i got a 2nd place award udontknowme, Fri, 11th Feb 2011
Just looked up antibubbles and found this site - I remember playing at my mother's sink in about 1964 when I was about 9 years old and observing this phenomenon. Lots of what I termed antidrips (those skidding on the surface) and occasional antibubbles (yes, I gave them the same term). I have also noticed the antidrips on the surface of very clear running water eg by small waterfalls / rapids. Peter, Wed, 4th May 2011
Noticed at my work that there were some spheres of what appeared to be water skittering across the water, but were visibly different from the bubbles which were slow in comparison. I asked others if they had noticed this occurrence themselves, but to no avail, they looked at me somewhat askance. Thank you for helping feed my curiosity. Trappedinbluecollar, Tue, 5th Jul 2011