Sunday, February 05, 2006

Learn how you can make antibubbles in your kitchen from soapy water.

What you need
    1) Water

    2) Clear bowl or tank

    3) Dishwashing liquid/detergent

    4) Beaker, jug or squirt bottle (tomato sauce or mustard bottles tend to work well)

What to do

    1) Fill the clear bowl to the very brim with water with a few squeezes of washing-up liquid in it)

    2) Keep some more of this liquid in the jug for the next step

    3) Gently pour (or squirt) the liquid from the jug (or bottle) onto the surface of the bowl.

    4) Watch beneath the surface as you pour and vary the speed at which you pour. If you are using a squirt bottle, you can also vary the angle you squirt at.

    ; 5) When you find the right speed, you will see antibubbles form as the stream of water breaks up beneath the surface.

    6) You can now watch these antibubbles move and sink downwards and they will eventually burst.

What to look for

Antibubbles are the exact opposite of bubbles: where bubbles are thin surface of fluid in air surrounding a pocket of air, an antibubble is a thin surface of air in fluid surrounding a pocket of fluid. You can watch these antibubbles move and sink downwards and they will eventually burst.

Dr Stéphane Dorbolo (who recently published research into the mechanisms of antibubble formation) said: "Antibubbles are mysterious phenomena but we now understand them much better. We have come up with a good model describing how they form and move and have also learnt more about the type of liquids you can create them in. We tried to create them in beer for fun, and didn't think it would be possible, but were amazed when we magaged to create giant antibubbles which lasted for almost two minutes and that moved around a glass of beer before bursting. "You can't create antibubbles in pure water, alcohol or oil. But beer is a special case because it is very similar to dishwashing liquid and contains what we call surfactants which is what you need to be able to produce antibubbles" We also found that when they die, or burst, they morph into a form of structure which we have nicknamed the jellyfish form because it looks very like a jellyfish swimming through water. It slowly moves and fades away until it disappears altogether."

What happens

The dishwashing liquid is a surfactant that tends to form membranes separating fluids and air. As you pour the liquids together, at the right speed, a thin layer of air can be trapped between the two bodies of fluid. As the fluids combine, a part of this film can wrap around a pocket of the fluid, forming an antibubble.

Things you can do

    If you disolve salt in the water that you pour in, this water will be denser than the water around it, so the antibubbles will sink.

    If you color the water in the jug, you can also make the antibubbles more visible, as well as assuring your self that the antibubbles actually contain water from the jug.

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