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Here is a fun science activity that an advisor of my friend sent him.

Hey guys:
The latest issue of science news had an article about anti-bubbles.
As you may know bubbles consist of a sphere of air surrounded by a
layer of water (and perhaps some soap). An anti-bubble consists of a
sphere of water surrounded by a layer of air. Much to my surprise
the internet is full of recipes and info on how to make
anti-bubbles. I tried one and found they are easy to make. My grand
daughter and I spent a couple of hours messing around with them.
I did the following:
1) take a clear and colorless container and fill with water. Add
several drops of dish washing liquid soap and stir but do not make
soap suds.
2) Take a clean plastic bottle that has an extended squirt tip with
an opening of about 2-3mm. I used an old plastic ketchup bottle, but
I suppose even a drinking water bottle would work.
3) half fill the bottle with the soap solution above.
4) holding the bottle tip at a 45 degree angle and slightly above
the surface of the liquid in the 1st container, gently squeeze the
bottle to cause droplets to fall into the clear container.
Be sure to have only a tiny distance separating the bottle tip and
the liquid interface.

This really works. You'll recognize the anti-bubbles because they
will be large in size compared to the others and take more time to
float to the surface.

At first, I was a bit skeptical that the bubbles I saw really
contained liquid instead of air. To prove this, I added a drop of
blue food coloring to the ketchup bottle liquid. Anti-bubbles which
contain liquid are then blue in color and are easily distinguished
from regular bubbles which have no color.
If you also add salt to the ketchup bottle the anti-bubbles will
sink instead of rise, giving further evidence that the anti-bubbles
do contain liquid and not air.
Add a layer of sugar water to the bottom of the clear container and
the anti-bubbles (made with the salt solution) will come to rest on
the layer of sugar water and remain stable a long time before
bursting.
This is really fascinating.
I can think of many ways this might be used in physics and physical
science. One could easily have students doing inquiry.

Try this and see what you think. You could write a new inquiry lab
centered around this.

DOC


John Hoffmann Ph.D.
MAE Science Director