Title: How do snow, sleet, and hail form?
1Lesson 25 How do snow, sleet, and hail form?
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3Have you ever packed a snowball or made a snowman?
4You cannot shape rain because it is liquid, and
as we know, liquids cannot have a shape of their
own.
5Snow is different, it is a solid, and solids have
a shape of their own.
We can change the shape of snow after it hits the
ground.
6Snow is one kind of solid precipitation.
There are other kinds
sleet
hail
7Snow, sleet and hail form in different ways.
8Snow
Water vapor condenses to form clouds. If the
temperature around the clouds if above freezing,
the vapor changes to liquid droplets.
9If, however, the temperature around the clouds is
below freezing, the vapor turns to tiny snow
crystals.
10The tiny snow crystals grow and grow.
When they become heavy enough, they fall to earth.
11Hail forms during thunderstorms.
Strong air currents keep raindrops moving in the
air for a long time.
As they move, they pass through many cold and
warm layers of air.
12In the cold air, raindrops freeze.
They change to ice beads.
In the warm air, water builds up around the beads.
Then the water freezes when they pass through
another cold layer.
13This happens over and over again. Each time the
icy beads become bigger.
Finally, they become hailstones, are too heavy
for the air currents to carry them, and they fall
to earth.
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