Cumulus Maximus: Test WEATHER you can make your own cloud!
Have you ever imagined yourself falling asleep on a cloud? Did you know that if you were to sleep in a cloud, you would wake up soaking wet!? There are many different types of clouds, but one thing they have in common is that they’re all made of water (or ice). But how do clouds form, and how is it possible that water can float above us in the air? In this experiment you’ll make your own cloud in a jar, and get to test the conditions that are required to make a cloud form!
This activity is not appropriate for use as a science fair project. Good science fair projects have a stronger focus on controlling variables, taking accurate measurements, and analyzing data. To find a science fair project that is just right for you, browse our library of over 1,200 Science Fair Project Ideas or use the Topic Selection Wizard to get a personalized project recommendation.
In order to understand cloud formation, we need to understand the processes of vaporization (water going from a liquid to a gas) and condensation (water going from a gas to a liquid). If you’ve ever boiled a pot of water, you’ve seen water change from a liquid to a gas. In liquid form, water molecules are packed very close together. This proximity allows the formation of hydrogen bonds between individual water molecules, so that each water molecule is connected to the water molecules surrounding it. You can observe this by looking at a droplet of water on a flat surface. Instead of spreading out flat, the water droplet holds a rounded shape. The droplet can hold this shape due to the strength of hydrogen bonds between the individual water molecules that form the droplet.
As you heat a pot of water, you add energy to the individual water molecules. When enough energy is added, the water molecules are able to break the bonds between them, and escape as a gas into the air. As these individual water molecules break away from the surface of the boiling water and rise above the pot, they lose energy (in the form of heat). As a result, these cooler water molecules condense into tiny water droplets, that we see as steam.
Cloud formation follows these same basic principles. As warm air rises (carrying moisture in the form of water vapor), it expands and cools. When this happens, the water vapor condenses into its liquid form. This condensation is the same type that you’ll find on your grass or car window on a spring morning. In a cloud, the water droplets attach to tiny dust particles floating in the air. Billions of these wet dust particles create a cloud!
In this experiment you will simulate cloud formation by rapidly changing the temperature of the water in the jar. You will experiment to determine what the important factors are in cloud formation, and how different conditions could change whether clouds form in our atmosphere.
Note: An adult should be in charge of pouring the hot water into the jar, as well as placing the lid on top of the jar. Steam rising from hot water can cause serious burns, and children should be warned to stand clear and observe each step.
The first 3 steps should be done in quick succession by an adult, while children observe from a safe distance.
Extra: Repeat this experiment using a different liquid (for example: juice or soda). See if there are liquids that produce different results than water. What are these results, and what do you think might account for the difference?
Extra: Repeat this experiment without using the aerosol spray. Does it still work? Why or why not?
Observations and Results
When you performed this experiment with the hot water, did you observe a cloud forming? This is what is expected. When you repeated the experiment with cold water, did you observe cloud formation? You shouldn’t have seen a cloud when you used cold water, because you need heat to generate enough water evaporation to form a visible cloud.
In this experiment you simulated cloud formation by rapidly changing the temperature of the water in the jar. When you poured the boiling water into the jar, the boiling water produced water vapor, and as this water vapor rose to the top of the jar, it was cooled by the ice cubes resting on the lid. As a result, the water vapor quickly condensed into tiny water droplets at the top of the jar. To simulate the dust particles that cause clouds in our atmosphere, we use an aerosol spray. The tiny particles released by the spray provide a surface to collect water condensation.
When you took the lid off the jar with the hot water, you may have noticed that your cloud remained fairly intact. Tendrils of it may have started drifting away, as the warm air in the jar began to escape into the room. However, when you dropped an ice cube into the hot water, you may have observed that your cloud started disappearing more quickly. This is because the hot water quickly cooled, so it was no longer releasing water vapor. Therefore, there was no vapor to condense and form a cloud.
More to Explore
Megan Arnett, PhD, Science Buddies
Science Buddies |
Evaporation, condensation, weather, atmosphere
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