How much does a cloud weigh?

That depends. Is it a big cloud, or a little cloud? What kind of cloud?

I don't know. I am going to guess that it weighs a lot. (Probably some thousand pounds or so, depending on how large the cloud is...)

Water = eight pounds a gallon
Pint of water = 1 lb

We need to know what kind of cloud it is, how large it is, etc.

So it depends!

Cloud Making Activity- (burner)
The lit paper put ash into the small containers air. When it was heated, this created a temperature difference between the ice at the top and the bottom of the container which was heated. This caused the water at the bottom of the container to form a cloud near the top.

Cloud Making Activity- (bottle)
The lit paper put ash into the gatorade bottle. When we started squeezing the bottle, we were creating rapid pressure changes. When you squeezed the bottle, there was no cloud, but when you let go, the cloud appeared. The water was forming clouds around the ash particles. Pretty cool.

Air Pressure

The effect of air pressure on a can is pretty interesting. We saw a pop can getting immediately crushed by moving it from a hot surface to a bowl of icy water, as the air pressure was expanding when it was hot, and the cold condensation inside the pop can crushes it. The same thing was done with a 55 gallon drum, although it took longer.

Materials for hardboiled egg experiment:
paper
bottle
hardboiled egg
napkins/paper towel
matches

Prediction: Egg gets sucked into bottle, lands on flaming paper, and the classroom smells like burning eggs for the next week.

The egg did get sucked into the bottle! And it smelled terrible.

Why did it happen? Because the flame inside the bottle was expanding the air pressure through heat, and when it went out, the air was cooling, and that made the air contract. Which sucked in the egg.