Water Cycle in a Bag

This is a really easy weather activity to put together and is also something that you can come back to over and over again for teachable moments. 

What you need: 

  • Ziploc bag

  • Permanent marker

  • Water

  • Blue food coloring

  • Tape

What to do: 

  • At the top of your plastic bag, on one side draw a sun and on the other side draw a cloud.  At the bottom draw some water (like a lake or ocean)

  • Pour enough water in to cover the bottom of the bag 1/4”-1/2” and add a drop of blue food coloring.

  • Seal the bag and tape it to a window that gets direct sunlight

  • Nothing will happen immediately, so check your bag a couple times a day over the next few days and observe what is happening. 

What’s happening: 

Evaporation, condensation, precipitation: that’s what’s happening! 

watercycle_rc.png

Water doesn’t just disappear from our planet. We started by pouring liquid water into the bottom of the bag like in a lake or ocean. That water evaporates, changing into a gaseous state.  As water vapor, it rises into the sky and forms clouds.  In the cloud it condenses back into liquid and falls back to the earth as rain.  In the cloud sometimes the water freezes to its solid state (ice).  It can fall out of the cloud frozen and melt on the way down to the ground. Once the water is back on the ground, it runs downhill until it finds a stream and flows into larger bodies of water. Then it starts the process all over again! The image above from NOAA shows even more ways water changes state on our planet.

Hannah Strong