# How Heavy is a Bubble?

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#### Updated on Feb 05, 2012

Grade Level: 7th - 9th; Type: Physics

### Objective:

This science project examines the relationship between the size of a bubble and how quickly it falls.

### Research Question:

How is the size of a bubble related to the speed at which it falls?

Have you ever used a bubble wand to make bubbles of all sizes simultaneously? If so, you may have wondered whether the smaller bubbles or the larger bubbles were more likely to hit the ground first. You probably can’t figure out the answer using a bubble wand, but you can figure it out using your own homemade bubble pipe.

### Materials:

• Pencil
• Foam cup
• Drinking straw
• Bubble solution
• Wide, shallow bowl

### Experimental Procedure:

1. Fill the bowl with bubble solution.
2. Poke the pencil through the side of the foam cup, near the bottom.
3. Remove the pencil.
4. Push the drinking straw through the hole so that it goes all the way inside the cup. This is your bubble pipe.
5. Turn the entire bubble pipe upside down and place it into the bubble solution.
6. Lift up the bubble pipe.
7. Blow into the straw very gently to make a bubble form on the top of the cup.
8. After a small bubble forms, twist the cup quickly to release the bubble. At the same time, hit the “Start” button on the stopwatch.
9. Time how long it takes for the bubble to hit the ground. Record your data in a chart like the one below.
10. Blow nine more small bubbles, and record how long it takes for them to fall as well.
11. Blow ten large bubbles, using the technique described above. Record how long it takes for them to fall in the second column of the chart.
12. Calculate the average time it took for each type of bubble to hit the ground by adding up each column and dividing the sum by 10. Compare the results.

Terms/Concepts: What were the earliest bubble-blowing devices created?; How much does air weigh?

References:

• Experiments With Bubbles, by Robert Gardner. Pp 57-58.

Keren Perles has worked as an educational writer, editor, teacher, and tutor of all ages. Her experience spans the subject areas, from science and math, to English and the Hebrew language.