The water cycle or also known as the hydrological cycle is a state that describes how water moves continuously on Earth. Water cycle through different stages include: Evaporation, Condensation, precipitation and flow. Then go back to the evaporation stage. The whole cycle begins again and hence the name “water cycle”.
Evaporation occurs wherever there is open water, eg at sea level, river or lake, when we sweat, when animals sweat and when plants die. As the sun heats up the exposed water, the water on the surface turns into steam and enters the air. Evaporation can occur at any temperature, but warm water evaporates faster than cold water. If we boil water, we can see steam rising from the surface. It is a quick and visible evaporation.
As water vapor in the air rises and reaches the upper atmosphere, cold temperatures cause them to release heat and turn back into fluids. These fine water droplets hang on the dust particles in the air to form clouds.
As water droplets collide and condense simultaneously in the upper atmosphere, they become larger and heavier.
Through rainfall, water returns to the surface of the earth. Some water flows down and ends in the sea, lakes and rivers.
In this simple experiment of “water cycle in plastic”, we will observe various stages of the water cycle process up close.
Plastic Bag Bending (zip)
Permanent color markers
Blue food dye
1. Warm the water until steam begins to rise but do not boil.
2. Add the blue food dye into the water to represent the seawater.
3. Pour water into a Plastic Bag zipper
4. Hang the bag over the door window using ribbon or yarn.
5. As the water evaporates, the steam rises and condenses at the top of the plastic bag. white clumps can be seen resembling clouds in the upper atmosphere.
6. After a while, water droplets appear on the inside of the plastic bag. As they get bigger, they will eventually slide down. Glide down like a flow stage that brings water back to the ocean.
7. If the water is still warm or if the bag is left in the window facing the sunlight, it will continue to flow through four different water cycle stages.