fog

We took this picture from our deck about a month ago. I like it because you can really see a little cloud of fog sitting over the valley. There are different types of fog, but they all form in basically the same way. Like clouds, fog forms when the air cools to a point (the dew point) at which water vapor begins to condense into tiny water droplets. Making fog in a jar is pretty simple and fun!

Materials:
Black paper
Gallon jar
Colored warm water
Matches
Gallon size bag of ice

1. Tape the black paper on the back of the jar, so you can't see through the jar.

2. Fill one third of the jar with colored warm water.

3. Light the match and hold it over the jar opening.

4. After a few seconds, drop the match into the jar and cover the top of the jar with the bag of ice.

You should see a small cloud of fog form. The particles of smoke from the match act as nuclei - tiny particles on which the water vapor can condense when it cools.

You can read more about fog here. It's a pretty detailed description about different kinds of fog, but it's accurate and informative.