You want the bottle to be mostly empty: if you leave a small amount of water in the bottom of the bottle, you will see a cloud of water vapor form at the end. [2] X Research source Bottles with smaller lids also tend to work better.
Recycle the label when you’re done with the experiment.
Starting the twist can be difficult. In some cases it can be easier if the bottle starts out slightly deflated. Remove the cap, squeeze the bottle a bit and replace the cap while keeping the bottle slightly squished. Make sure the cap is tightly screwed on to the top of the bottle before beginning this step.
Keep the bottle pointed away from your face and others while you are twisting the bottle. While it is unlikely for the bottle to pop during this step, it is possible.
Another way to pop the cap off is to hold the bottle between your legs and then twist it with your hand. If the cap does not fly across the room, there wasn’t enough air pressure built up inside the bottle. Untwist the bottle, blow into it to refill with air, and try again. [5] X Research source
This is also how clouds form in the sky. At cooler temperatures, the water vapor forms around dust particles to condense. [6] X Research source
If the plastic cracks at any point in the bottle, it will no longer work for this experiment.
Don’t share bottles with multiple people to avoid the spread of germs.
The bottle should begin to twist more easily the more times you use it. At some point, the plastic will likely crack and you will not be able to use that bottle anymore.
Remember, never aim the bottle towards a person or an animal. Avoid pointing the bottle at your face as well.
