BUBBLES   more experiments

Experiment 1: Bubble Formula.

Materials: White corn syrup, confectioners’ sugar, different kinds of dishwashing soap (Dawn is the best), cup, spoon. (Hint:  try making scented bubbles with scented dishwashing soap!)  You’ll also need a bubble wand, which you can make out of a pipe cleaner or wire.

Procedure:

Mix ¼ cup of warm water with 2 tablespoons of one of the dishwashing soaps. Test your concoction. How big can you blow your bubbles? How long do they last in the air? • Now add 1 T. corn syrup. Test your concoction again. Do you notice any difference in your bubbles? • Now add 1 T. of confectioners’ sugar. Stir until all ingredients are completely dissolved. Try your solution one last time. Are your bubbles getting any bigger?

Extensions: Try a different combination of detergents and thickening agents. Which of your formulas produces bigger bubbles? (Hint: the more detergent used, the bigger the bubble! What other hypotheses can you make and test out?) Also try building differently sized bubble wands out of pipe cleaners or wires. How big can you blow your bubbles now?

Hint: One of the strongest, most sturdy bubble solutions can be made by combining 2 parts Dawn detergent with 4 parts glycerin (available at most drug stores) and 1 part white Karo brand syrup (available at most grocery stores).

Experiment 2: Are Bubbles Always Round?

Materials: pipe cleaners. Procedure: Bend pipe cleaners into as many shapes as you can think of – square, heart, triangle, etc. Can you get your bubble to take the shape of your wand??

The Science: 

• Bubbles form when water molecules stick together, creating surface tension. When molecules stick together too firmly, bubbles don't form as easily. Adding soap helps decrease the surface tension, making bubbles easier to form.

• Bubbles pop because the water in them evaporates. Glycerin and other thickening agents have water-holding properties that delay evaporation, making the bubbles last longer. When you blow bubbles on a rainy day, they last longer because there is more moisture in the air. What do you think happens on a sunny day? How about a windy day?

• Bubbles are "minimal surface structures" (as are balloons). This means that they always hold the gas inside of them with the least possible surface area – and the shape with the least surface area for any given volume is always a sphere. This is why bubbles are always round, even when you blow them through a square wand. When bubbles are surrounded by other bubbles, they can appear to flatten out, but once the other bubbles are removed, the bubble will revert back to it’s round shape.

• We see colors in a bubble through the reflection and the refraction of light waves off the inner and outer surfaces of the bubble wall. You can't color the bubble itself since its wall is only a few millionths of an inch thick. Instead, a bubble reflects color from its surroundings. The thicker the bubble’s walls, the more intense the color.

• You can put your finger or arm into a bubble without popping it – by wetting it first, you prevent the molecules from coming “unglued.”