A soap bubble is air surrounded by water and soap. It is held together by surface tension. Water alone has too much surface tension. Soap lowers the surface tension of water allows it to have the right surface tension for stable bubbles. Air trapped inside provides pressure from the inside, and the air outside the bubble adds pressure from the outside.
Which substances cause soap bubbles to last longer?
- 4 bowls
- Measuring cups
- Measuring spoons
- Liquid dishwashing soap
- Lemon juice
- Corn syrup
- Pipe cleaners or 4 small bubble wands
- Gather the necessary materials. Make four bubble wands from the pipe cleaners if other bubble wands are not available.
- Combine the ingredients to make four different bubble solutions. Allow the solutions to sit for an hour. Solution 1 1 cup plus 1 tablespoon water 2 tablespoons liquid dishwashing soap Solution 2 1 cup water 2 tablespoons liquid dishwashing soap 1 tablespoon glycerin Solution 3 1 cup water 2 tablespoons liquid dishwashing soap 1 tablespoon corn syrup Solution 4 1 cup water 2 tablespoons liquid dishwashing soap 1 tablespoon lemon juice.
- Place a bubble wand in each solution. One at a time, blow a bubble. Catch the bubble on the wand and use the stopwatch to see how long the bubble lasts. Repeat 10 times for each bubble solution. Record your results.
- Calculate the average length of time each bubble lasted. To find the average, add all the times for each solution and divide by 10.
- Analyze the data. Which solution made the longest lasting bubble?
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