In this experiment, you will see how water from the ground gets into the air to form clouds and then falls back to the ground as rain!
As the sun heated up the water in the cup, some of the water evaporatedinto a gas called water vapor. You can't see water vapor, but you can see what happened next. The water vapor turned back into a liquid and little drops of water formed on the inside of the bag—this is called condensation. When several droplets of water stuck together, they became heavy enough to pull each other down the sides of the bag. If you left this project taped to your window for long enough, all of the water from inside the cup should eventually end up in the bottom of the bag!
This is exactly how clouds form and make rain. Water from rivers, lakes, streams, or oceans evaporates into the air when it is heated up by the sun. As the water vapor rises up in the air, it condenses, or starts to cool down and turns back into a liquid. Then, droplets of water start to stick together as clouds. When enough droplets stick together in the clouds, they become large and heavy and are pulled down towards the earth by the force of gravity. When water drops fall from clouds, it is called rain. Sometimes the droplets freeze before they get to the ground and become hail, sleet, or snow!
Did you know you can make a cloud? It will be much smaller than the ones in the sky that bring us rain, but it forms in the same way as those in the sky.
Clouds are formed when water warms up and changes into a gas called water vapor, which rises up into the air. As it rises higher in the sky, the water vapor cools down and turns back into tiny drops of liquid. Inside the jar, some of the warm water evaporated into water vapor. Then, as water vapor hit the cold metal bowl of ice, it turned back into tiny droplets of liquid water. The smoke from the match that was held in the jar helped make the cloud easier to see. The tiny droplets of water stuck to tiny bits of smoke in the air between the warm water and the ice. In a real cloud, tiny pieces of dust floating in the air work the same way as the smoke did in your jar, and the water droplets form around the dust. As more water changed into water vapor and then back into tiny water droplets, the cloud grew.
When you removed the container of ice, the water vapor didn't condenseback into drops of water anymore, but just rose out of the top of the jar, taking your cloud with it!
To learn more about baby animals, visit this Teaching Tip.