Energy Transfer
What type of energy transfer from the Sun heats Earth’s surface?
radiation
A measure of how much water vapor is in the air.
What type of cloud usually produces hail?
cumulonimbus
What are uplift and gravity?
Uplift is a force of strong rising air that pushes things up. Gravity is the force that pulls precipitation down.
Why do hailstorms tend to happen in warmer climates?
The heat is needed to make water vapor and uplift.
What happens to water molecules when they gain heat energy?
They move faster. If they gain enough energy, they evaporate.
When air gets warmer, does it become more dense or less dense?
Less dense.
Does hail form in warm air or cold air high in the clouds?
Cold air high in the clouds.
Why can strong uplift keep a hailstone in the air?
When the hailstone is light, uplift can balance out or be stronger than gravity. This keeps the hailstone up.
Why are hailstorms so windy/gusty?
Because when there is more uplift, it causes gusts of wind.
How does the Sun help start the water cycle?
The Sun heats water with radiation. This causes evaporation.
Why does warm air rise and cold air sink?
Warm air is less dense, so it rises. Cold air is more dense, so it sinks.
How does a small ice piece grow into a hailstone?
It is lifted up and down in the cloud. Each time it goes up, more water freezes onto it.
What happens when uplift becomes weaker than gravity?
The hailstone falls to the ground.
Why doesn’t hail form in weak storms/storms with weak uplift?
Weak storms do not have strong enough uplift to keep ice in the air long enough to grow.
How do conduction and convection help move water vapor into the sky?
The ground warms the air by conduction. Warm air rises by convection, carrying water vapor upward.
How can convection cause clouds to form?
Warm air rises and cools as it goes higher. When it cools, water vapor turns into tiny drops and forms clouds.
Why does hail have layers of ice?
The hailstone moves up and down in the storm. Each time it goes into humid air, a new layer of ice freezes around it.
Why are larger hailstones found in storms with stronger uplift?
Strong uplift keeps hail in the air longer, so it can grow bigger before falling.
A storm has heavy rain but no hail. What might be missing?
The storm may not have strong enough uplift or cold enough air high in the cloud.
If the Sun stopped heating Earth’s surface, which part of the water cycle would slow down first?
Evaporation
A cold air mass meets a warm, humid air mass. What happens?
The cold, heavier air pushes under the warm air. The warm air rises, cools, and may form clouds and rain.
When hailstones grow larger in a storm, which process changes water vapor into ice, adding layers of ice?
In a storm, when uplift and gravity are equal in strength, what happens to a hailstone?
It stays suspended (floating) in the cloud.
Why would a cloud with very few CCN produce less hail?
Fewer CCN means that less condensation and ice can form, so hailstones stay small or do not form.