In the first Evaporate Some Water experiment, we explored the water cycle and how water can be converted into water vapor using only the energy from the sun. But what happens to water that is not in a stream, lake, or ocean?
The Experiement
Supplies: Two clear glasses of the same size, a marker pen, a piece of cardboard that will cover one of the glasses, tape, food coloring (optional).
What to do: Put a vertical strip of tape on the side of each glass. Measure out enough water to fill each glass about 3/4. Fill each glass with the exact same quantity of water. Add food coloring, if available. On the piece of tape, mark the water level on each glass. Tape the cardboard cover onto one of the glasses so that it does not fall off. Place both glasses in direct sunlight and leave them for a full day of sunlight. Then observe the level in each glass. Which glass had more water evaporated out of it?
What is happening: The piece of cardboard blocked the water vapor from reaching the atmosphere, so the water stayed inside the glass. Blocking the top of the glass created a miniature closed ecosystem, where the water evaporated into the space in the top of the glass, then condensed and returned to the pool of water below. The Earth is a closed ecosystem on a grand scale, with our atmosphere trapping the water and keeping it here, just like the cardboard kept the water in the glass.
Links
To find out more about closed ecosystems and instructions on how to make one of your own, visit NASA’s Climate Kids website!