Water, a colorless liquid comprised of two atoms of hydrogen and one atom of oxygen, covers more than 70% of the Earth's surface. Animals, plants and human beings must have water to survive and flourish. Water is the main component of an animal's blood and a plant's sap – and water makes up two-thirds of the human body.
Water exhibits many properties that provide interesting subjects for simple physics experiments and science fun for kids.
Displacement: Something Has to Give
Object: To show that two forms of matter cannot occupy the same space at the same time:
- Fill a clear drinking glass half full of tap water
- On the outside of the glass, mark the water level with a piece of masking tape
- Tilt the glass and carefully slide several marbles, one by one, inside the glass
- Set the glass upright
- What happens to the water level?
Solution: Substances Fitting Neatly Together
Object: To show that the empty spaces around water molecules can be filled in with other substances to form a solution:
- Place a long strip of masking tape down the outside of a large, clear glass jar
- Pour one cup of warm water into the jar and mark its level on the masking tape
- Add another cup of warm water and mark its level on the masking tape
- Empty the jar and dry the inside thoroughly with a paper towel
- Add one cup of sugar to the water and stir well with a drinking straw or plastic spoon
- What happens to the level of the liquid in the jar? Why doesn't one cup plus one cup equal two cups?
Suspension: Particles That Keep Their Distance
Object: To show that some particles will be suspended in water rather than dissolving into a solution:
- Pour 3/4 cup of cornstarch into a small mixing bowl
- Slowly add 1/3 cup of tap water (food coloring may be added) and stir to mix well
- Roll a large piece of the mixture between your palms and shape it into a ball. Notice how the mixture feels as you roll it
- Stop rolling the ball and hold it on your open palm
- What happens?
Buoyancy: The Ability of an Object to Float
Object: To show that an object that is heavier than water can be made to float
- Fill a large bowl almost to the top with water
- Roll a small piece of modeling clay into a two-inch ball
- Place the ball on the surface of the water and let it go
- What happens?
- Remove the ball from the water and mold it into the shape of a small flat-bottomed boat with high sides
- Place the clay boat on the surface of the water
- Now what happens?
Water: A Scientific Wonder
Water is an amazing substance that offers endless possibilities for elementary science experiments. Please see the images following this article for illustrations of the experiments showing displacement, solution, suspension, and buoyancy. Click on an image to enlarge it.
For additional science experiments, see:
- Afterimage Experiment for Kids – Arts and Crafts for Science Fun
- Science Experiments for Kids: Learning About Gravity
- Science Projects for Kids – Easy Experiments With Light
- Science Projects for Kids – Easy Water Experiments
Sources:
Bonnet, Robert L. Science Fair Projects: Physics. NY: Sterling Publishing,1999.
Breckenridge, Judy. Simple Physics Experiments With Everyday Materials. NY: Sterling Publishing,1993.
Carol Wells - Carol Wells holds a B.A. degree in English. As a freelance writer, she takes the most pleasure in writing articles for children.
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