I'm forever blowing bubbles
Warm spring weather calls for days on the patio and this is a way to have fun and learn something news. Experiment: Why are bubbles round? Materials: Clean jar, dish washing soap, water, baking pan, gelatin, straws and three feet of string. Process: In the jar mix a 1/2 cup of dish soap, one pack of gelatin and 5 cups of water. Let the mix stand in the refrigerator for two days. Pour the mix in the baking pan. Place the string through the two straws. Wet your hands and with a straw in each hand, dip the straws into the bubble mix. Pull the straws out the of mix, pull them apart as a frame and swirl in the air. Result: A giant bubble. Why? The large bubble is a result of adding a large amount of air. When you pull the straws apart, the air pushes out in all directions along with the molecules of soap. The soap molecules want to stay together so their tug creates the elastic skin of the bubble.
Bubbles are round because as the skin of the bubble contracts it forms the smallest surface for air and that surface is round.