What is the main idea of the passage?

Dew forms when grass cools nearby air to the dew point and water vapor condenses into liquid drops. (The passage traces surface cooling, air cooling, dew point, and condensation.)

Why can grass become cooler than nearby air?

It loses heat toward the clear night sky. (The second paragraph identifies heat loss toward the sky as the source of surface cooling.)

What does “condense” mean here?

change from gas into liquid (Invisible vapor becomes visible liquid droplets when condensation occurs.)

What can reduce nighttime surface cooling?

clouds (The third paragraph says wind and clouds can reduce cooling.)

How Dew Finds the Grass: Level 1 Reading Comprehension Questions

After a clear night, grass may sparkle with water even when no rain fell. The water is dew. It forms when a surface cools enough for water vapor in nearby air to condense.

Grass loses heat toward the night sky and can become cooler than the air above it. Air touching the blades cools too. When it reaches the dew point, some invisible vapor becomes liquid droplets on the surface.

Dew does not fall from the sky like light rain. It forms directly on cool objects. Wind and clouds can reduce cooling, while humidity affects how soon condensation begins.

The drops reveal water that was already present as vapor. Cooling changed its form, not its identity.

Comprehension questions