Observations and results
How much water were you able to collect? You can try leaving it for longer and see how much more you can accumulate.

Not everything can be separated out from water this way. Tiny particles, such as dust or chemical pollutants, can still find their way up into the sky. In fact, raindrops form around small pieces of dust in the clouds, and polluting "acid rain" can contain chemicals from burning fossil fuels.

What are other ways you can think of to purify water?

Share your water cleaning observations and results! Leave a comment below or share your photos and feedback on Scientific American's Facebook page.

Cleanup
Don't drink the water, but you can use it to water plants! You can use the moist dirt for houseplants, outdoor plants or to start a new plant from seed.

More to explore
"Sour Showers: Acid Rain Returns" from Scientific American
"Warmer Climate Produces Less Rain" from Scientific American
The Water Cycle game from the Environmental Protection Agency
"What Is Acid Rain?" overview from the Environmental Protection Agency
A Drop of Water by Gordon Morrison, ages 4–8
The Water Cycle: Evaporation, Condensation & Erosion by Rebecca Harman, ages 9–12
           
Up next…
High Seas: What Happens When the Glaciers Melt?

What you'll need
•    Small bowl
•    Ice cubes
•    Modeling clay
•    Toothpicks
•    Warm water

6 Comments

1. 1. rahulbhuju 12:02 AM 6/1/11

   Instead of placing just a plastic,it's better to use black plastic or polythene bags.As black absorbs more heat than any other colors so the process goes as fast as it could...

   Reply | Report Abuse | Link to this

2. 2. skip_kovacs 12:53 AM 6/3/11

   In "Preparation", I think you should nestle the empty glass so it is BELOW the rim of the mixing bowl. If it is even with the rim the marble will not be able to drop the level of the plastic film low enough to have the condensed water drip into the glass without the film also sealing itself against the glass's rim.
   
   And I disagree with ruhulbhuju in the second comment: if this is a teaching exercise, we should use clear film to see the evaporation/condensation process, even if it is less efficient than it would be with black film.

   Reply | Report Abuse | Link to this

3. 3. Steven Brown 11:53 PM 6/23/11

   Better yet, use sunlight to crack water into hydrogen and oxygen, making a fuel that stores solar energy for later use. As for how to contain and transport hydrogen, there is a wonderful atom called carbon that can bond to four hydrogen atoms, creating a gas called methane for which a distribution network already exists.

   Reply | Report Abuse | Link to this

4. 4. Steven Brown in reply to Steven Brown 03:56 AM 6/24/11

   The use of carbon in this manner can be carbon neutral, because carbon dioxide can be reacted with hydrogen, in a reaction powered by sunlight, to make methane.

   Reply | Report Abuse | Link to this

5. 5. clevitan 01:06 AM 7/28/11

   This is also a Boy Scout survival technique. Instead, dig a hole in the ground (replaces the bowl) and put lush vegetation in it (replaces mud).
   To disagree with rahulbhuju above, the plastic sheet has to be clear- it must be cooler than the mud, since it is the condenser, and the mud has to be as hot as possible.

   Reply | Report Abuse | Link to this

6. 6. syedasrarahmed 08:28 AM 1/28/12

   The diagram explains quite better.

   Reply | Report Abuse | Link to this