WEATHER AND CLIMATE The Earth’s Atmosphere The Earth is surrounded by layers of air which make up the Earth’s atmosphere. What is Weather? Weather is the outside conditions at any time. Many factors affect the weather such as the sun, atmosphere, temperature, water, and air pressure. Lesson Checkpoint: What is weather? Words you may hear when listening to a weather report: Humidity is the amount of water vapor in the air. Air pressure: As air gets close to the Earth’s surface and warms up, the particles in the air move farther apart. The warm air then pushes down with less pressure, and then rises forming an area of low pressure. Low air pressure results in a cloudy day. As air gets close to the Earth’s surface and cools, the particles in the air move extremely close together, and this thick, cooler air sinks, forming an area of high pressure. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
High air pressure results in clear skies. When air moves from an area of high pressure to a place with low pressure, WIND is created. Air Mass: A huge body of air that has practically the same temperature and humidity. The movement and interaction of air masses cause most weather conditions. Fronts: A front is an area where two air masses meet. A warm front forms when a warm air mass bumps into a cold air mass that is not moving or is moving at a slow pace. Warm fronts usually move more slowly than cold fronts. A cold front forms when a cold air mass bumps into a warm air mass that is moving fast, not moving, or is moving at a slow pace. Climate: The word climate refers to the typical weather throughout the year in the same area. Lesson Checkpoint: What is an air mass? © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
The greenhouse effect is the rise in temperature that the Earth experiences because certain gases in the atmosphere trap energy from the Sun. The Sun’s energy and heat would escape back into space if the Earth did not have certain gases to trap it and it would be MUCH colder here on Earth, too cold to live. Tools of the Weather Trade Meteorologists use many tools to help them predict and record the weather each day. A thermometer is used to measure temperature. A hygrometer measures humidity. A barometer is used to measure air pressure. An anemometer is used to measure the speed of the wind. A weather vane measures wind direction. A rain gauge is used to measure the amount of rainfall. © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.
Meteorologists use weather maps and charts to record measurements and information about the weather happening in many areas. Lesson Checkpoint: What does an anemometer measure? Severe Weather Conditions Sometimes weather can be severe causing great damage to the Earth’s surface. A hurricane is a storm that forms over oceans with winds reaching over 74 miles/119 kilometers per hour. A tornado is a funnel-shaped column of air that touches the ground destroying anything in its path. It is smaller but has heavier winds than a hurricane. A drought is a long period of dry weather. A flood is a large overflowing of water onto land that is normally dry. Lesson Checkpoint: What is the difference between a flood and a drought? © Copyright NewPath Learning. All Rights Reserved. Permission is granted for the purchaser to print copies for non-commercial educational purposes only. Visit us at www.NewPathLearning.com.