Articles

    Science of Soap Bubbles


    Kids, did you ever wonder what a turtle shell, a bee's honeycomb, a soccer ball, a chicken wire fence, and a bag full of bubbles have in common? All you will need to find out is a quart size zip-lock bag, a plastic straw, and a bubble solution. To make the bubble solution, mix 4 parts of water to 1 part of liquid detergent. For example, measure 1 cup of water and add 1/4 cup of detergent. Add the detergent to the water, and stir gently. Adding about 1/2 teaspoon of sugar makes longer lasting bubbles.

    Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

    Place 1 tablespoon of bubble solution in the plastic bag. Close the bag almost completely, leaving just enough room to slip the straw into the bag. Gently blow through the straw to fill the bag with bubbles. Now study the bubbles that formed. Are the sides of the bubbles curved or flat? How do their sizes and shapes compare? Do most of them have the same number of sides?
    You'll find that many of the bubbles inside your bag should have six-sides, which makes them hexagons. Many hexagon shapes can be found in nature. Spider webs, some insect's eyes, and certain plant stems are based on this shape.

    How thick is a soap bubble? The film is one of the thinnest things that we can see without using a magnifying glass. It is about 5000 times thinner than a human hair! What's inside the bubbles? It is always a gas, and most have ordinary air inside. The bubbles that you blow contain more carbon dioxide because this is a gas that we exhale. Bubbles in soda pop are filled with carbon dioxide, and those in boiling water are filled with vaporized water or steam.

    [Since different detergents have different bubble-making abilities, you may have to experiment by using different amounts of detergent, water, and sugar until you get the nicest, longest-lasting bubbles.]

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    Kathleen Carrado Gregar, PhD, Argonne National Labs 
    [email protected]
    November 1995

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    Reference: WonderScience , vol. 9, no. 1, January 1995. (call 1-800-333-9511 for subscription information to WonderScience).