Cloud in a Bottle

Contributed by Alan Feria

Introduction

The idea of creating a cloud at home sounds rather fascinating yet highly improbable. However, what if I told you that we can do it and that it is much simpler than you thought! Follow along with me and I’ll teach you how to create a cloud within the comfort of your home! 

Materials

• Water bottle 16 oz. (empty or full) 
• Rubbing alcohol
• Optional items: 
  • 2 Liter soda bottle (clean and dry) 
  • Cork 
  • Duct tape
  • Nail, needle or drill bit. 
  • Scissors 
  • Bike pump, or air compressor. 
  • Ball pump needle 

Procedures for method one: 

1. First I will be doing the method which involves none of the optional items! So to start off we will be getting a 16 oz water bottle and dumping out the water if it is full, if it is empty pour in a small quantity of water (H2O) shake around and throw out. 
2. After this cover the bottom of the bottle with rubbing alcohol and swirl around, try to coat the walls of the bottle evenly. 
3. Now all that is left to do is to twist the bottle and remove the cap (be sure to not be facing anyone when you let the cap loose as it may hit someone). 
4. If you would like to repeat the experiment you can simply inflate the bottle once more, or as many times as you’d like. 

Procedures for method two:

1. So to start off make sure that your soda bottle is clean and dry
2. Next, get the cork and fit it to your bottle. If you need to you can get your scissors and cut it down so that it fits nice and snug. The tighter the fit the better!
3. Following that you will want to make a small hole with either your nail, needle, drill bit or whatever you have that can make a small hole. Be sure that the whole you make is smaller than the diameter of the bike pump needle. 
4. Going back to the bottle, pour in a teaspoon of rubbing alcohol and swirl around so that it can evenly coat the walls of the bottles. 
5. Lastly, insert the bike pump needle into the cork and insert the cork into the bottle and pump air into the bottle using the bike pump. 

What should we expect? 

Well once you reach a decent amount of pressure within the bottle you can either remove the bike pump or cork, whichever is easier. Once removed you should be able to see a dramatic cloud form within your bottle (be sure to not be facing anyone when removing the cork/needle)  

Concepts

Invisible water molecules are always present in the air that surrounds us and in the bottle. That is what we call water vapor. Twisting the plastic bottle compresses the air molecules inside. When we release the cap, we are permitting the air molecules to expand. When the air molecules expand the temperature lowers and they get colder. As they cool, the molecules start sticking together (water / alcohol vapor, and air molecules). This combination allows small water drops to form. Just like the clouds in the sky. 

Further Investigations

• One question I want to leave to you at home is how does the ratio of alcohol to water change the final outcome of the experiment? 

Citations

“Make Rain Clouds in a Bottle.” National Geographic Kids, 14 June 2019, kids.nationalgeographic.com/explore/science/make-clouds-in-a-bottle/.