A quick activity that seeks to get participants to understand how clouds form, why it rains, and how precipitation and evaporation are part of a process called the water cycle.
- Ziploc bag
- Blue food colouring
Preface this activity by asking your group a few curiosity-building questions, like: Why is it that the Earth isn’t constantly flooded even though it rains and snows? When the water levels in the ocean “drop,” what does that mean? Where does the water go? Give them a few moments to answer. They may or may not know the answers but regardless they will still be able to enjoy the activity. Begin by explain how the Earth is the biggest recycler. It has a limited amount of water, and since all living things depend on it, the Earth has to reuse it, and reuse, and reuse it. This process is called the water cycle.
- In the top left hand corner of the Ziploc bag, draw a sun, in the top right corner, draw some clouds, and along the bottom of the bag, draw some water waves.
- Pour some water into the bag (just enough to fill about 1/5 of the bag) and then add a few drops of blue food colouring.
- Seal the bag and tape it to a window. Watch the action over the next few days and talk about what’s going on inside the bag.
- Take this experiment to the next level by creating a scrapbook. Take a picture of the bagged water cycle each day (at the same time) for a week and jot down in a notebook what you see (leave some space at the top. Print out all of the images, paste them in the notebook with the corresponding notes, and observe a week’s worth of change in the photographs!
- Sharpie markers and food colouring can stain clothes and skin, so be careful or wear proper clothing and gloves.
On warmer days when the sun is shining, the sunlight warms up the water in oceans, lakes, and in the ground, causing frozen water to melt and liquid water to evaporate into vapour (a gas). Once the vapour is in the sky, it begins to cool and change into a liquid again. This is called condensation and is why we have clouds in the sky. Similar to a soaked sponge, when the air can’t hold anymore condensed liquid, it falls back down to the ground as rain, snow, or hail – precipitation. From here the water cycle will begin again.
Hollowell, Malia. “Water Cycle in a Bag.” Playdough to Plato. Last updated February 11, 2015. Retrieved May 29, 2018, online from: https://www.playdoughtoplato.com/water-cycle-bag/