Students who demonstrate understanding can: Collect data to provide evidence for how the motions and complex interactions of air masses result in changes in weather conditions.
Clarification statement: Emphasis is on how air masses flow from regions of high pressure to low pressure, causing weather (defined by temperature, pressure, humidity, precipitation, and wind) at a fixed location to change over time, and how sudden changes in weather can result when different air masses collide. Emphasis is on how weather can be predicted within probabilistic ranges. Examples of data can be provided to students (such as weather maps, diagrams, and visualizations) or obtained through laboratory experiments (such as with condensation).
Assessment boundary: Assessment does not include recalling the names of cloud types or weather symbols used on weather maps or the reported diagrams from weather stations.
Official wording from the Next Generation Science Standards (NGSS Lead States, 2013). NGSS is a registered trademark of WestEd. Neither WestEd nor the lead states and partners that developed the NGSS were involved in the production of this page, and they do not endorse it. View on nextgenscience.org
When a cold front sweeps through, the temperature can plunge, the wind can swing around and a sunny afternoon can turn stormy within an hour. Students collect and interpret data, from weather maps and station readings to classroom experiments, to show how the movement and collisions of air masses cause the weather at one place to change over time.
Air masses are huge bodies of air that take on the temperature and humidity of the region where they formed: cold and dry over northern land, warm and moist over tropical oceans. Air flows from areas of high pressure toward areas of low pressure, carrying those air masses along. Where two different air masses meet at a front, warm air is pushed upward, cools and its water vapor condenses into clouds and precipitation. Weather is described by temperature, pressure, humidity, precipitation and wind.
Forecasts give probabilities rather than certainties, such as a 70 percent chance of rain, because the atmosphere is complex. Recalling cloud names or map symbols is not required.
Air flows from high pressure toward low pressure. Letting air out of a balloon gives a simple, memorable picture of the direction.
The number is a probability of measurable rain at a location, not the fraction of time it will rain.
Weather is the condition of the atmosphere over hours or days; climate is the long-term pattern over decades.
Cold air is denser and sinks. At a cold front, the cold air wedges under the warm air and pushes it upward.
A weather station records: 1 pm, 24 °C, pressure 1008 mb, wind from the south; 3 pm, heavy rain and gusty winds; 5 pm, 15 °C, pressure 1016 mb, wind from the northwest. What happened, and how do the data show it?
Answer: A cold front passed the station: the 9 degree temperature drop, 8 millibar pressure rise, wind shift and burst of rain all point to a colder air mass replacing a warm one.
Have students track a week of local weather data alongside daily weather maps and mark when fronts pass. A simple tank with cold blue water and warm red water released from opposite ends models how denser cold air pushes under warm air. Discussing real forecasts, including how their percentages are worded, builds the probabilistic idea.
Assessment items commonly present a data table or weather map and ask students to explain the change in conditions at one location.
Original questions written for this standard. Choose an option or type your answer, then press Check. Every question has a worked explanation.
Answer: A) From high pressure to low pressure
Air moves from areas of higher pressure toward areas of lower pressure, which we feel as wind.
Answer: D) Warm and moist
Air masses take on the properties of their source region; a warm ocean gives warm, humid air.
Answer: C) The warm air is forced upward, often causing clouds and storms
Denser cold air wedges under the warm air and lifts it; the rising air cools and its vapor condenses.
Answer: 8 (also accepted: 8 degrees, 8 °C)
21 - 13 = 8 degrees Celsius.
Answer: A) There is a 3 in 10 likelihood of measurable rain
Forecasts are probabilities; 30 percent means rain is possible but less likely than not.
Answer: front (also accepted: a front, weather front)
A front is where two air masses meet, and weather often changes quickly there.
Represent data in tables and graphical displays to describe typical weather conditions expected during a particular season.
A full lesson with slides, activities and an exit ticket on air masses and changing weather, pitched to grades 6-8 and editable in PowerPoint or Google Slides.
Make a lesson →A printable, differentiated worksheet on MS-ESS2-5 with an answer key, ready in about a minute.
Make a worksheet →Turn air masses and changing weather into a quiz students answer online that marks itself, with a class summary for you.
Build a test →No. Recalling cloud types and weather symbols is excluded; students interpret provided data to explain changes.
Weather maps, diagrams and visualizations, station data, or laboratory experiments such as condensation activities.