The Cloud Case: The Experiment

"Maybe this experiment will help you understand clouds," Professor Less said to me. "We're going to make a cloud in a bottle."
(You can't watch the Prof. perform the experiment like I did, but you can perform it yourself. Just carefully follow the instructions in bold type.)

You'll need the following materials:
a large clear plastic bottle with cap
a measuring cup
cold and hot water
matches (Handled by a grown-up)

Pour 1/3 cup of cold tap water into the clear plastic bottle and put the cap tightly back on. Then shake the bottle for 30 seconds and set it on a table. Squeeze the bottle and then release it. Repeat this process several times.
Do you notice anything different about the bottle? Inside the bottle?

With an adult helping you, remove the cap from the bottle. Hold a match over the bottle's mouth. Now, blow out the match by quickly squeezing the bottle. Then slowly release the pressure on the bottle to draw the smoke into it. Replace and tighten the cap on the bottle. Then squeeze and release it several times.
Do you see anything different about the bottle now? Did a cloud form in the bottle? Why would a cloud form now that you've added smoke?

Clean out the bottle well and pour 1/3 cup of hot tap water into it. Then repeat Step #2 again, using hot water.
What happened differently this time? Was there a bigger cloud than before? Why do you think it was bigger?

"Well, I hope you've learned something from that experiment " the Prof. said to me after it was over.

"Yes, but how much have I learned?" I asked him, wondering. I had to know. I'm an investigator. It's what I do.