Making clouds for science project This is about a group project for our science class and we've decided to do a physical model on clouds.

We could use liquid nitrogen and hot water to demonstrate the formation of the clouds and we are aware that it doesn't form like that in the nature. 

I just wanted to ask, what's the pressure required for clouds to form? I found out that it's -10o C temp. but nothing about pressure (lower than normal but don't have the exact number)

Any ideas? :( I'm starting to feel pretty desperate. 

Can we use the nitrogen to decrease the temperature to -10 and then pressure, and wait for liquid water to condensate? 

Any kind of answer will be appreciated. Thanks :)
To form a cloud, generally speaking, pressure does not play a significant factor (with the exception of the effect on temperature).

If you want to prove that to yourself, go outside when it is foggy and measure the air pressure. Fog is a cloud, and pressure likely hasn't changed as much as it does in the vertical direction.

As far a forming a cloud, it is actually relatively easy. You only need to decrease the temperature to it's dewpoint. You may want relatively dirty air, so that the solute effect makes it easy to form drops. Silver iodide would be good for this.

For reference, the Kohler curve describes the saturation needed for cloud droplets to form.