The Water Cycle

Make your own window water cycle experiment.

Every living thing on the Earth needs water to live. Did you know that the water on Earth today is the same water that has been on the Earth for nearly 5 billion years? So it is possible you are drinking the same water that thirsty dinosaurs were drinking 65 million years ago. This is because the water is constantly travelling around our planet in a cycle. This is called the water cycle. 

The water cycle is the journey water takes from the sea to the sky, to the land and back to the sea.

1st part of the journey

The sun heats up the water in the oceans, rivers and lakes. Some of this water turns into water vapour or steam. This is called evaporation.

Just like how puddles of water become smaller and smaller and then disappear when the sun comes out after a rainstorm. (The water evaporates).

2nd part of the journey

The water/vapour goes up into the sky where the water cools down again and turns into clouds. This is called condensation.

Clouds are really made up of lots of very small drops of water.

3rd part of the journey

The tiny water drops in the clouds bump into each other and become bigger drops and make the clouds grow. When the water gets too heavy the water drops down to the ground as rain and eventually ends up in the rivers and oceans again. This is called precipitation.

Try out this cool experiment to see how it works:

Ziplock Bag Water Cycle Experiment

What you need:

1 medium sized clean used plastic ziplock bag
Small cup/container
Blue food colouring
Permanent marker pen(s)
Masking/Painters tape


  • Use the permanent marker pen to draw some clouds and sun near the top of the bag (near the ziplock). Then draw a straight line with some fishes below about 5cm up from the bottom of the bag. If you have more than one colour you can get creative and colour these in but make sure you don’t colour below the water line blue.
  • Pour some tap water into a cup and add a few drops of blue food colouring. Stir it gently until it is all mixed together.
  • Carefully pour the water into the plastic bag up to the water line and close the ziplock. Make sure it is properly closed.
  • Using the tape stick the bag up on a window making sure it is securely fastened. Choose a window that gets a lot of sunshine.
  • Watch what happens. If it is a sunny day you might see something happen within just a few hours.