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Paper Clip Sailing

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This lesson developed by Reach Out!

Recommended Age Groups: Elementary

Guiding Question:

1. Why do some things float on top of water?

2. What is surface tension?







Each person or pair needs:
  1. A clear glass or plastic salad or mixing bowl
  2. Water
  3. Fork
  4. Paper clip
  5. Dish Soap

Room Preparation

Need ample elbow room. Spills may happen.

Safety Precautions


Procedures and Activity



  1. Fill clear bowls with water.

  2. Now comes a balancing act! Hold the fork with one hand and rest the paper clip on the prongs.

  3. Slowly and carefully sit the fork into the bowl of water until the paper clip floats off the fork and rests on top of the water. This may take some practice!

  4. Why doesn't the paper clip sink? Squat down to get eye level with the bowl of water. Observe what is happening. Can you see how the paper clip is a little bit down in the water? Or does the paper clip totally rest on top? Can you see kind of a surface or skin-like appearance on the very top of the water?

  5. We are seeing evidence of water surface tension.

  6. Put a drop of dish water soap into the water. Put it in somewhere away from where the paper clip is floating. What do you think will happen?

  7. Why does the paper clip sink down into the water? What did the soap do? Share ideas. If no one comes up with it, share that when we added the drop of soap, we interrupted the pull and tug of the water molecules on top and below. This broke up the force and skin-like surface on top, so the paper clip dropped.

  8. Repeat experiment and encourage use of terms: water, molecules, surface, and surface tension.


Again, ask the guiding questions:

1. Why do some things float on top of water?

2. What is surface tension?

Listen for evidence that they have come to a better understanding about water, molecules, and surface tension. If possible, have them share this lesson and experiment with others. When we "teach" something, we definitely come to understand it! This is a fun experiment to share with friends.

Extension Ideas

Careers Related to Lesson Topic

Prerequisite Vocabulary

The smallest amout or unit of a substance, like water, that still has all the parts of the origial substance.
Surface Tension
When the molecules of water inside the bowl attract and pull on the molecules of water on the top surface. This is called "surface tension." It is as though the water molecules below the surface are pulling and tugging on the water molecules at the top.
The liquid that comes from clouds as rain and creates the streams, rivers, lakes and oceans on our Earth.

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