Weather Station

Desert Island

What it does

This experiment shows how cities become islands of heat.

What you need

This project does not require any materials. However, you must conduct the experiment outdoors on a summer night. Be sure to bring an adult with you for safety.

What to do

After a particularly hot summer day, go outside just after the sun goes down.
With your hands, touch objects that have been in the sun for most of the day. Some possibilities include the sidewalk, a driveway or road (being careful to watch for cars), grass, the roof of a car, rocks, bushes, and dirt.
Rank the objects by how hot they feel.

What it's all about

Objects absorb the sun's heat during the day. At night, some objects hold onto heat longer than others. In general, man-made items tend to hold onto heat longer than natural items. For instance, an asphalt road will stay hotter than desert dirt. A car will hold onto heat longer than a tree.

Before Phoenix became a big city, summer nights often dropped down into the 70s. Today, temperatures rarely sink below the mid-80s. This is partly due to the addition of roads, parking lots, buildings and cars that retain the day's heat well beyond the sunset.

Remember, be sure you have a parent, teacher, or other adult help you!