Lesson 24 What is precipitation Can you imagine

Lesson 24 What is precipitation?

Can you imagine our planet without rain? All the water would evaporate.

All of the oceans, rivers, lakes, and streams would dry up. There would be no water for plants or animals

Nothing could live.

Luckily, this does not happen. Water does evaporate, but it always comes back to earth.

Water comes back to earth from clouds. Water that falls to earth from clouds is called precipitation. Precipitation may be liquid or solid.

There are 5 kinds of precipitation. snow rain drizzle hail sleet

Rain and drizzle are liquid precipitation. They form only when the temperature is above freezing. At sea level, freezing is at 0° C or 32° F.

Snow, hail, and sleet are solid precipitation. They form when the temperature is at freezing or below.

Why do clouds give up their water? Why does the rain fall back to earth? The answer to the second question should be easy…… Gravity…. but what is the answer to the first question?

Clouds are made up of billions of tiny droplets of water. The droplets are very light weight. So light weight that rising air keeps them bouncing around.

As they bounce around, the droplets collide. When this happens, the droplets combine and make bigger droplets. This happens over and over until they become large enough to be drops.

Drops are much bigger and heavier than droplets. Rising air can no longer hold them up, so they fall to earth.

Rain is made up of drops, drizzle is a fine spray of droplets.