Earth and Space Science: Weather Dynamics

Unit Overview

It is difficult to imagine a day going by where someone does not talk about the weather or climate change, yet few people are able to base their discussions on a thorough understanding of the scientific principles that explain the Earth's weather and climate systems. To help develop and strengthen that understanding, students will investigate the factors that govern our global climate, focusing on the role of energy and water movement throughout the atmosphere and hydrosphere. Students will develop an understanding of the methods and technologies that meteorologists use to collect, display, and analyze weather data through the collection and analysis of local weather data. They will also explore weather forecasting and its limitations, cultural perspectives on weather, the impact of severe climate and weather on our planet and the changing of the Earth's climate.

K-12 Related Topics in Science

Saskatchewan Science Units (2005)

Grade 2 - Weather
Grade 4 - Predicting Weather
Grade 6 - Earth's climate (Optional)
Grade 7 - Temperature and Heat (Optional)
Grade 9 - The Atmosphere (Optional)

Pan-Canadian Framework Units

Grade 1 - Daily and Seasonal Changes
Grade 2 - Air and Water in the Environment
Grade 4 - Rocks, Minerals, and Erosion
Grade 5 - Weather
Grade 6 - Space
Grade 7 - Heat
Grade 8 - Fluids
Grade 8 - Water Systems on Earth
Grade 10 - Weather Dynamics

Key Questions

What is the difference between weather and climate?
What are the impacts of severe weather on our planet?
How do meteorologists collect data?
What are the scientific principles that explain global weather dynamics?
How do meteorologists forecast the weather locally and globally?
What major natural and human factors influence climate change?
What are the effects of global climate change on our environment?

Key Concepts

Weather is defined as the day to day environmental conditions in a location. Climate is defined as the weather conditions of a location averaged over many years. The earth has a variety of climatic patterns, which consist of different conditions of temperature, precipitation, humidity, wind, air pressure, and other atmospheric phenomenon. Global climate systems are driven by the uneven heating of the surface of the earth by solar radiation. The cause of the uneven heating is the 23.5° tilt of the Earth's axis which affects how directly sunlight falls on a given location on the earth's surface. This uneven heating creates convection currents within the atmosphere and oceans, producing winds and ocean currents. The rotation of the earth curves the flow of winds and ocean currents through a process called the Coriolis Effect.

The cycling of water in and out of the atmosphere plays an important part in determining local and global climatic patterns. Water evaporates from the surface, rising and cooling, condensing into clouds and then into snow or rain, and falling to the surface where it collects in rivers, lakes, and porous layers of rocks.

Many severe weather events occur because of sudden movement of air masses of unequal temperature and moisture content. The atmosphere has a tendency to reach a stable state with a relatively equal distribution of temperature and moisture. Sometimes air masses move rapidly resulting in a warm, humid air mass becoming trapped below a lighter, cooler air mass. The warmer, moister air begins to rise and expand, and its water vapour condenses. This condensation releases heat, causing the air mass to rise higher and faster. At some altitude, this warmer air cools rapidly, causing the moisture that is being carried upward in the air mass to be released as precipitation. This could take the form of a blizzard, a thunderstorm, or a hurricane.

Earth's climate has changed radically in the past and many scientists expect it to continue changing. Natural causes include the effects of geological shifts such as the advance or retreat of glaciers over centuries or a series of huge volcanic eruptions in a short time. Even relatively minor changes of atmospheric content or of ocean temperatures, if sustained long enough, can have widespread effects on climate. Humans are contributing to these changes, although the ultimate long-term effects are not clearly known. (AAAS, 1989)