* Physical Changes: Involve changes in the form or appearance of a substance, but not its chemical composition.

* Example: Water changing from a liquid to a gas (evaporation) or a gas to a liquid (condensation)

* Chemical Changes: Result in the formation of new substances with different chemical properties.

* Example: Burning wood, which produces ash, smoke, and gases.

How dew forms:

1. Evaporation: During the day, water evaporates from the ground and bodies of water.

2. Condensation: As the air cools down at night, the water vapor in the air condenses onto the cooler surface of the leaf, forming tiny droplets of water.

Key Point: The water in the dew is still H2O (water), just in a different physical state. No new substances are formed.