Unit 4: Lesson 4 HMH Science

Front

What happens in a low-pressure system?

Back

Air rises and cools.

Front

What is an air mass?

Back

An air mass is a large area of air that has the same temperature and humidity.

Front

How do air masses cause weather changes?

Back

Air masses can force warm air to rise, causing moisture to condense and form clouds, leading to weather changes.

Front

What type of weather do low-pressure systems bring?

Back

Low-pressure systems bring stormy weather.

Front

What type of weather do high-pressure systems bring?

Back

High-pressure systems bring dry, clear weather.

Front

What is a cold front?

Back

A cold front forms where a cold air mass meets a warm air mass, causing the warm air to rise.

Front

What is a warm front?

Back

A warm front forms where a warm air mass meets a cold air mass, causing the warm air to rise over the cold air.

Front

What happens when warm air rises?

Back

When warm air rises, it cools and can lead to cloud formation and precipitation.

Front

What is humidity?

Back

Humidity is the amount of water vapor present in the air.

Front

How does temperature affect air pressure?

Back

Warm air is less dense and rises, leading to lower air pressure, while cold air is denser and sinks, leading to higher air pressure.