With all the rain we have been experiencing in the Triad lately, we decided it would be the perfect opportunity to have a lesson on the water cycle!
For this experiment you will need the following:
- Plastic ziplock bag
- Sharpie (to draw clouds and waves)
- ¼ cup of water
- Blue food coloring
- Painter’s tape
Begin your experiment by drawing clouds around the top and water around the bottom of your plastic bag. This will serve as a visual aid of the water cycle and how it works.
Next, fill your plastic bag with ¼ cup of water, and add about 4 drops of food coloring.
Seal your bag shut, and hang it in a window (we recommend using painter’s tape since it is easy to remove once your experiment is over.)
Now it’s time to let nature run its course! Check on your bag periodically and notice how much condensation your baggie collects over time.
What’s the science?
In nature, the sun’s heat causes water to evaporate from streams, lakes, rivers, and oceans. As the water vapor rises, it condenses to form clouds when it reaches cooler air. When the clouds are full of water, or saturated, they release some of the water as rain. Then the cycle starts over again.
The same principle can be applied to your experiment. Over the next few days, you will see that the water has warmed in the sunlight and evaporated into vapor. As that vapor cooled it began changing back into liquid, just like a cloud. When enough water condensed, the air couldn’t hold it anymore and the water fell down in the form of precipitation.
Remember, it is important to note that an experiment uses a variable (something that changes) to answer a question. To turn this demonstration into an experiment, you have to change something! Check out these questions to get you started:
- Does the location (North facing, South facing, partial shade, full sun, etc) of the window have any impact on the cycle?
- Does the amount of food coloring used have any impact?
- How does the outside temperature impact the experiment?
Give it a try and let us know how your experiment turned out on our Facebook, Instagram, or Twitter pages using the hashtag #gscscience!