Weather And Water Cycle Science Activities | Create A Cloud In A Bottle
How do Clouds Form?
Clouds are like large lakes in the sky. How do they get there? When water from the ground evaporates, it rises with warm air. This water, in an invisible gaseous state, is called water vapor. The pressure decreases the higher up in the atmosphere. The air is cooler as well. As the water vapor rises, the pressure lowers, and the water vapor cools. Eventually, the temperature reaches the dew point. This is when the atmosphere is at a temperature where the air can no longer hold the water vapor; some must condense back to a liquid.
To make the change, the water vapor needs a non-gaseous surface. This is usually in the form of smoke, dust, ash, or salt in the atmosphere. This is called the condensation nucleus. Think of the tiny particles as cloud seeds. The cooling process allows the water molecules to stick to the dust and each other and creates a cloud. It is visible because of the dust particles. The more water and dust in a cloud, the darker it will be. It is amazing that a cloud is liquid water floating in the sky.
Cloud in a Bottle
If you are looking for a lab that models the troposphere (where our weather takes place), this is it. Students will expand their knowledge of the water cycle and learn how clouds form. Yes, it is a real cloud. It may not stay long, but kids of all ages will be amazed. This lab is great for the classroom, science camps, and museums and makes a fantastic science fair project.
Supplies
Fizz Keeper
1 or 2-liter bottle
Hot Water
Matches (Teacher Uses)
Measuring cup
Safety goggles
Procedures
1. Pour 50 ml of hot water into your bottle.
2. This is the adult step.
We need a little dust. An adult will light a match. Let it burn for a second. Stick it in the opening of the bottle. Blow it out. Hold it in the mouth of the bottle until it stops smoking. Drop the match into the bottle.
3. Quickly screw the fizz keeper tightly on the bottle.
4. Swirl the water around the bottle, ensuring no condensation on the sides. We want to see inside the bottle.
5. Pump the fizz keeper 50 times. This can be tricky. You may be able to do fewer pumps. Some Fizz Keepers are better than others. You may need 60 pumps or more. If the pressure seems too great, STOP Pumping. SAFETY FIRST.
6. While watching the center of the bottle, quickly and carefully unscrew the fizz keeper to let the pressure out. It will happen very quickly. Keep your eye on the center of the bottle. You will see a puff of a cloud form. It may go away quickly or stay for a few seconds.
The video is not the best quality, but it shows you what happens well. The bottle was pumped 100 times. Our Fizz Keepers put a very small amount of air in the bottle.
What is Happening?
The hot water provides the warm air needed to evaporate the water and allow it to rise. The smoke serves as the condensation nucleus. The final thing needed was a change in temperature and pressure. The Fizz Keeper pumps a small amount of air into the soda bottle. The more pumps, the more molecules in the bottle will collide and compress. This increases the pressure and the temperature. This allows more water to evaporate in the bottle. The bottle is now a high pressure temperature environment.
The real atmosphere is a low-pressure and cool environment. To do that, the fizz keeper was unscrewed. This immediately releases gas, causing the pressure to decrease. The air in the bottle is allowed to expand, and the temperature decreases. The water vapor condenses onto the condensation nucleus (smoke and dust), and a cloud quickly becomes visible. This is not exactly like the atmosphere, so in most cases, the cloud will not stay long. Make sure to unscrew the fizz keeper quickly and carefully to cause a quick change in pressure.
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These complete science and STEM units are ready to go. Gather the supplies, print the booklets, and organize the unit.
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