This instructable will teach you how to make a cloud in a bottle. It's quite simple. This is all you need.

-Matches(take three just in case you mess up)
-A clear plastic bottle,preferably an empty Lipton Tea bottle(make sure it still has a cap)
-Running water

You will understand why Lipton Tea bottles are good for this soon enough.

This is my first instructable, so go easy on the comments.

I'm not liable for what you do with the matches.

Step 1: Prepare the Bottle

Get your Lipton Tea bottle and clean it out (don't use soap) Fill the bottle with water from your sink or hose or whatever. Now empty it out. Dry only the outside of the bottle. You only have little droplets in the bottle now, right? Good.

Step 2: Test Your Bottle

OK, we're getting to the good part. Close the bottle with the cap and squeeze really hard.

-When you squeeze, the air pressure inside the bottle goes up, and so does the temperature.
-When you release, the air pressure inside the bottle goes back down and so does the temperature.

Squeezing the bottle was to give you a science lesson and to check for leaks. If there are no leaks, good, if there are, get a new bottle and repeat steps 1 and 2.

Step 3: YAY! Fire!

So, now were really close to the fun part. I'm now going to tell you why Lipton Tea bottles should be used.
1.They're flat and totally see through, unlike most bottles which have designs which alter visibility so you can't see inside the bottle.
2.They are really tough! Most bottles are smashed or crushed when you squeeze them too much. These bottles are as tough as nails.Or maybe not quite...

Get ready for the fun part! Get a match and light it. Grab the bottle and put the side where the cap goes on toward the match(see picture)Blow out the match and stick it inside the bottle make sure plenty of smoke gets inside the bottle. (the more smoke the denser your cloud) Squeeze the bottle and let go. A cloud appears. This effect should last about 15 minutes of cloud-making fun. You can reuse the bottle when the clouds stop forming.
I included a video for your viewing pleasure.