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Water Vapor Experiments

Water vapor is the gaseous form of water. Water has three distinct forms that are crucial to the life cycle on earth. The liquid form of water, found in oceans, lakes and streams, becomes a gas in the heat and reforms in the cool air of the upper atmosphere as clouds. It returns to the earth as liquid rain or solid ice.

Water Cycle
- Water evaporates from oceans, lakes and streams, condenses as clouds, and then returns to the earth as rain and snow. Recreate this cycle with a large bowl, a coffee mug, a sheet of plastic wrap and a rubber band or string. Place the coffee mug inside the bowl. Add water to 1/4 the capacity of the bowl. Do not allow any water to drop into the coffee mug. Cover the bowl with the plastic wrap. Secure the wrap to the bowl with a string or rubber band so that it is airtight. Set the bowl outside in the sun on a warm day for 10 to 20 minutes. Water droplets will gather on the underside of the plastic wrap as the water from the bottom of the bowl turns to water vapor and then returns to a liquid form on the plastic wrap. Remove the plastic wrap. Note whether the cup is empty or contains water.
Make Water
- Make your own water with a birthday candle, a plate and a drinking glass. Light a birthday candle. (Kids, ask your parents to do this for you). Set the candle on a plate. Cover the entire candle with a clear drinking glass and watch. As the fire of the candle heats the air under the glass, the oxygen will bond with the hydrogen atoms in the air. When the oxygen and hydrogen atoms have bonded, the fire will go out. Pick up the glass and look inside. Note the water droplets that formed when the oxygen bonded with the hydrogen. The composition of a water molecule is two hydrogen atoms plus one oxygen atom (H2O).
Attract Water
- Water vapor surrounds us all the time in varying densities. Humid climates have higher densities of water vapor than dry climates. Turn the water vapor in the air into liquid with a cold glass of water. Fill a glass with ice and water. Leave the glass outside or in your home at room temperature. Return after 10 minutes. Note the amount of water on the outside of the glass. Water vapor in the air will turn to liquid in contact with the cold glass.
Sublimation
- Ice is the solid form of water. Ice can change directly into water vapor without first becoming a liquid. Likewise, water vapor can turn into a solid without first taking the liquid form of water. The process is known as sublimation. To view sublimation at work, purchase dry ice. Take dry ice out of the freezer and set it in a stew pot or bowl. Watch the vapors emanate from the block of ice. These vapors are the gaseous state of the solid ice as it sublimates.

Astronomy