Bacteria?

Are there bacteria that produce water as a waste product? Or at least something close enough to be filtered?

Tubes

Does the venturi effect produce an appreciable amount of moisture?

Fans

Questions:

1. At what wing span does the wake turbulence from a fan become pronounced enough to affect the airflow to the sides/rear?

2. What size of fan is needed to create an appreciable current flow? I guess this depends on wind speed so perhaps need to gather data on local airflow speeds?

Lens

1. How does a lens focal length determine the heat generated when sunlight is focused?

2. What is the maximum temperature a magnifying glass can generate and how does this relate to the answer for 1?