Surface Tension Science Projects
Surface tension is caused by the cohesive and adhesive properties of water and other liquids, which allow them to resist other forces. Surface tension makes it possible for water to form droplets, for some insects to run on the surface of water and for liquids to form a dome-like shape at the top of a full container. Science projects offer fun ways to experiment with surface tension.
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Observing Surface Tension
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Observe surface tension by taking a beaker and filling it until it is full. Place it on a flat surface and use a dropper to add drops of water, one by one. The surface of the water will gradually change from flat to rounded; looking at it from the side will provide the best view. Be ready for a spill; surface tension eventually gives out. You can also use a dropper to place drops of water on coins to observe the shape surface tension gives water.
Floating a Paperclip
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Surface tension makes it possible to float a paperclip, which should sink. First place a paperclip vertically in a beaker of still water. It will sink to the bottom. Then carefully place another paperclip horizontally on the surface of the water. It will float because the surface tension creates a membrane-like force. If you disturb the water, however, you will break the surface tension and sink the paperclip. You can also float a needle.
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Floating Pepper
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Shake pepper into a beaker filled with still water. The particles of pepper will float because of surface tension. Then disturb the surface tension by putting your finger in the water or adding a drop of liquid soap to the water. The pepper will sink because the surface tension is broken.
Separating Glass Slides
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Use a dropper to place a drop of water between two clean glass slides. Press the slides together and then try to pull them apart. They will be more difficult to pull apart because of the adhesive properties of surface tension. You can also feel this phenomenon by placing a dish on a wet counter and then lifting (or trying to lift) the dish.
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References
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