Awesome Chemistry Experiments With Water for Teens

Creating a Tornado in a Bottle

• This experiment demonstrates factors that affect the strength of a tornado. Remove the caps from two plastic soft drink containers. Glue the outsides of the two caps together so the assembly can be screwed on to the bottles. After the glue dries, secure the caps by winding duct tape around their edges. Ask an adult to drill holes through the centers of the two caps. Fill one bottle with colored water and glitter. Keeping the bottle with water on the bottom, and the empty bottle on top, attach the caps to the two bottles. Invert and horizontally rotate the bottles. As the glittery water twists down into the empty bottle, the horizontal spinning, together with gravity, causes a vortex that looks like the vortex formed by a real tornado as a result of wind shear, centrifugal force and changes in atmospheric pressure. Invert the bottle and repeat the experiment, systematically varying the speed, size and number of rotations. Describe the strength of the tornado as the conditions change.

Getting Eggs to Float

• This experiment shows how buoyancy is affected by water density. Pour 6 ounces of water into a 20-ounce glass. Stir in half a tablespoon of salt until it is completely dissolved. Carefully add a small raw egg still in its shell. Note whether the egg drops to the bottom of the glass or floats. If the egg drops, stir in more salt, in increments of half a tablespoon, until the egg floats. Repeat the experiment using 10 ounces and then 14 ounces of water. Try the same experiment with large and then jumbo eggs. Also try hard-boiling the eggs. Each time record the amounts of water and salt used -- and whether the raw or hard-boiled, small, large or jumbo egg -- dropped to the bottom of the glass or floated. Whether the egg drops or floats depends on the density of the egg, and the ratio of salt to water, or the density of the water. How does increasing the size of an egg affect its buoyancy? How does hard-boiling an egg affect its buoyancy?

Bending a Stream of Water

• Static electricity will bend a stream of water in this experiment. Turn on the water so that it comes out in a very thin stream. Run a nylon comb quickly through your dry hair a dozen times to create static electricity in the comb. When the comb is held near the stream of water, the water will bend toward the comb. You also can do this experiment with a balloon. Rub the balloon against your dry hair or a sweater to create the static electricity. Then hold the balloon near the stream of falling water. The charged comb or balloon attracts the molecules of water, so the stream bends. Repeat the experiment after increasing the size of the stream, and again after wetting your hair or the sweater. How do you explain the results?

Using Salt Water as a Conductor

• This experiment shows that pure water does not conduct electricity, but salt water does. Cover two tongue depressors (or craft sticks) with aluminum foil. Get three, six-inch pieces of insulated copper wire and strip a half-inch of insulation off each end. Tape one end of a wire to the positive pole of a 9-volt battery; tape the other end of that wire to the threaded metal base at the bottom of a light bulb. Tape one end of another wire to the tip of the light bulb, and tape the other end of that wire to the top of a tongue depressor. Tape one end of the last wire to the top of the other tongue depressor, and tape the other end of that wire to the negative pole of the battery. Test the circuit by bringing the two tongue depressors together so their tips touch. Do not continue the experiment until the bulb lights up, demonstrating that the connections are secure. Then place the tips of the tongue depressors about an inch apart from each other in a bowl containing a cup of distilled water. What happens to the light bulb? Take the tongue depressors out of the bowl and stir in a teaspoon of salt until it dissolves. Put the tongue depressors back in the water, about an inch apart from one another. Even when the sticks are not touching each other, the bulb should light up because salt water acts like a wire connecting the sticks and completing the circuit. Repeat the experiment adding a tablespoon of salt rather than a teaspoon. Does the light bulb shine brighter than before? Why? This experiment can also be done using a buzzer instead of a light bulb.