When dew forms on grass overnight, which of the following statements is true? A) The process is accompanied by an increase in temperature B) The process is accompanied by a drop in temperature ?

1 Answer
Mar 3, 2015

Completely against intuition, answer A is true.

When you turn water into steam, you need energy to do that.
Turning liquid into vapour needs energy. You will certainly notice this when you're wet, and a wind is blowing.

The other way around: if water vapour condenses, it will release energy.

So the water vapour condensing on the grass releases energy (warmth). So the temperature goes up (a tiny little bit, depending on the amount of everything and the temperature you start with).