Water Cycle in a Bag

Have you ever wondered what makes it rain? The rain is just a step in a larger process called the water cycle. The water cycle describes the continuous movement of water within the Earth and its atmosphere. The easiest way to help kids understand this concept is by performing science experiments like the water cycle in a bag experiment.

The water cycle describes how the water on the surface of the Earth evaporates and rises to the atmosphere in the form of vapor. In the atmosphere, it cools and condenses into clouds and falls back to Earth in the form of precipitation. Performing science experiments for kids like the water cycle in a bag helps children see it with their own eyes. This helps them understand their lesson on the water cycle and precipitation better.

Here is a step by step guide to performing the water cycle experiment in a bag:

Things You’ll Need for Water Cycle in a Bag

Creating a water cycle in a bag is extremely easy and doesn’t need a lot of materials. Here is a list of things you’ll need to make your own water cycle bag:

  • A medium sized ziplock bag or any resealable plastic bag
  • Permanent marker
  • Tape
  • ⅓ cup water
  • Blue food coloring
  • A window, which receives a good amount of sunlight
  • Notebook
  • Pencil

Steps to Create Your Own Water Cycle Bag

Ready to make it rain indoors? Then, follow these simple steps to create your own water cycle bag:

  • Step 1: Place the ziplock bag or resealable plastic bag on a flat surface. Using the permanent marker, draw the water cycle on the bag without puncturing it.
  • Step 2: Add a drop of blue food coloring to the ⅓ cup of water and stir it. 
  • Step 3: Hold the plastic bag upright and pour the blue colored water into it. Ensure that the bag is only half full. Seal the bag and ensure that it isn’t leaking.
  • Step 4: Now, find the sunniest spot on the window and tape the bag to the window at a slight angle. This simulates the runoff and collection stages of the water cycle. Ensure that the tape is secure and the bag won’t fall off.
  • Step 5: Keep checking on your water cycle bag over the next few days at different times. Write down your observations in your notebook.

Results of the Water Cycle Experiment in a Bag 

Over the next few days, you’ll observe several changes in your water cycle bag. First, you’ll notice water droplets forming on the bag. Slowly the water droplets get bigger and start dropping down the sides of your bag, leaving blue streaks. Eventually, the water recollects at the bottom of your water cycle bag.

The Science Behind the Water Cycle in a Ziplock Bag

The water on the surface of the Earth evaporates due to the Sun’s heat and rises to the atmosphere in the form of vapor. This vapor cools and condenses to form rain and snow clouds and eventually falls back to the Earth in the form of precipitation. This continuous movement of water within the Earth and its atmosphere is called the water cycle. 

The water cycle experiment in a bag shows you all 4 stages of the water cycle, evaporation, condensation, precipitation and collection. The water in the water cycle bag first warms up because of the sunlight and evaporates into vapor. As the vapor cools it condenses like a cloud, these are the tiny water droplets on the surface of the bag. When enough water condenses and becomes heavy, the air can’t hold it anymore. The water droplets, which are very large now, fall down into the pool in the form of rain. 

In nature, when it rains or snows, the water goes back to a body of water like rivers, lakes, oceans, groundwater etc. But in our water cycle bag, the water vapor cannot escape. So, the vapor sticks to the sides of the bag to form the water droplets, showing you the water cycle.

Learn more about the water cycle with this water cycle worksheet.

Water Cycle in a Bottle

If you find that the ziplock bag doesn’t stick to the window and falls off, you can perform the water cycle experiment using a bottle too. Just fill a plastic bottle with ⅓ cup of water dyed blue with food coloring and screw the cap on tight. Turn the bottle upside down and place it inside a transparent plastic cup. Now draw the water cycle on the bottle, and your water cycle bottle is ready. Place the bottle inside the cup in a sunny place and observe the water cycle over the next few days.

For more science worksheets, experiments, activities and games, check our kids learning section.

Frequently Asked Questions on Water Cycle in a Bag

What is the water cycle?

The water cycle describes the continuous movement of water within the Earth and its atmosphere in the form of evaporation, condensation and precipitation.

How does the water cycle in a bag work?

The water cycle in a bag shows kids the 4 stages involved in the water cycle. First, it shows how the water heats and evaporates, becoming vapor. Then the vapor condenses into a cloud in the atmosphere. Eventually, the condensed water gets heavy and falls to the Earth in the form of precipitation (rain or snow). This water gets collected in the water bodies of Earth.