Surface tension is a fascinating and a huge topic covered in elementary science. Most schools use boring textbooks to teach these concepts, but others use real experiments to demonstrate these concepts. In this Instructable, 3 experiments will be shown on how to discover surface tension and all the amazing things H2O does with it! Let's Get Started!
Step 1: Fireworks in Milk
What? It's true. With just milk, a toothpick, detergent, a bowl and food coloring, you can turn your beverage into a fireworks show. (Don't drink the milk afterward!)
- Fill your bowl halfway full with milk.
- Drop 2 drops of every color food coloring you have in the center of the dish.
- Dip your toothpick in detergent and dip the tip in the center of the food coloring.
- Observe the fireworks effect
How does it work?
Because of the surface tension of the milk, the food coloring stays at the top, floating just above the surface. When the detergent disrupts the surface tension of the milk, the food coloring spreads out in all directions, not wanting to sink to the bottom. Because of this, a fireworks display is shown. The detergent acts as a disrupter, which is something that disturbs the equilibrium of a chemical; in our case H2O.
Step 2: Levitating Water
Of course, water can't just float in the sky! No, it can't, but it can defy gravity! Using only a mesh, a glass of water, a rubber band, and a piece of cardboard, this experiment shows students the concept of surface tension-Upside Down! This proves to them that surface tension is actually there, and because it forms right between the mesh, the water doesn't pass through.
- Fill a glass of water 1/2 way full with water.
- Cover the top of the glass with the mesh and secure it with a rubber band.
- Use the cardboard to cover the top of the glass.
- Suddenly and rapidly flip the glass and remove your hand from the cardboard.
- It should stay on!
- Now remove the cardboard completely.
- Wow your whole classroom!!!
Step 3: Dead Paperclip, Alive Paperclip
OF course, there are no such things as dead and alive paperclips! Actually, they can look like they are though... With a container of water, detergent, a paperclip, and a toothpick, you can create an alive->dead paperclip.
- Fill the container with water.
- Carefully balance the paperclip on the surface of the water. (Let the kids do this so that they can really see the surface tension. If you were to drop a paperclip into the water, it would just sink.)
- Dip a toothpick into the detergent and dip that into the container of water.
- Automatically, the paperclip falls to the bottom of the container, dead!
Step 4: RECAP
Using 3 fun experiments, we learned about surface tension and how it affects our everyday lives. Through the three experiments, we were able to see that this invisible force was indeed there. Soap, which acted as a disturbant, took away the surface tension in the experiments. One cool thing you could do when you are in nature is to look at the water striders. These amazing creatures have the ability to walk on water, and guess how?
That's right, its Surface Tension!