How do you build a simple Dew Collector?

Question

Does anybody know what the principals of dew collection are? And how we can make a dew collector with simple household materials? This is actually for my son’s Boy Scout troop. They would like to build one next weekend as their “Gadget” for a competition.

Thanks in advance.

Answer 1

The basis is remarkably simple:

1) a large non-absorbant surface area (for generating dew)

2) a collection method

3) placement in area without any obstruction to the sky

One of the best methods is to bury a empty coffee can (or similar) nearly rim deep.  Stretch out a piece of plastic/tarp over the burried can, elevating the edges using dirt piles and anchoring the corners down with rocks.  Poke a small hole in the center of the plastic/tarp directly over the coffee can.  Place a couple small rocks around the central hole to cause the plastic/tarp to form an inverted umbrella shape.

The surface area will collect dew, and gravity will force it to roll downhill towards the rocks & hole, spilling into your collection container.  The larger the collector the more dew you collect.

You must place your dew collector where it has an open view to the night sky, not obstructed by tree limbs directly overhead.

Answer 2

It is a great thing to learn. It could save your life. You take a large sheet of transparent plastic and drape it over a hole loosely. In the middle of hole is a cup. You put a rock in the middle of the sheet so that sheet is angled into the cup. Condensation collects on the plastic, and gravity causes it to drip into the cup.