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 is an amazing substance that offers endless possibilities for elementary science experiments. 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
Bonnet, Robert L. Science Fair Projects: Physics. NY: Sterling Publishing,1999.
Breckenridge, Judy. Simple Physics Experiments With Everyday Materials. NY: Sterling Publishing,1993.