Air Masses and Weather Fronts
Aligned to MS-ESS2-5 — Next Generation Science Standards.
What this lesson teaches
Large bodies of air take on the temperature and moisture of the region where they form — warm and humid over tropical seas, cold and dry over polar land. When two different air masses meet, the boundary between them is a front, and the mixing there is what produces most of our changing weather.
Worked example
When a cold air mass pushes into warm, moist air, the heavier cold air wedges underneath and shoves the warm air up quickly. That rising warm air cools, its water vapor condenses, and you get the tall thunderclouds and sudden storms typical of a cold front.
Practice questions
- Track your local weather for a week and note the temperature and any rain each day.
- Watch a TV or online weather map and describe what happens to the weather as a front moves through.
- Explain why warm air rising over cold air often leads to clouds and rain.
Watch the lesson
Every lesson comes with a video taught in English and Spanish — the same video the QR code in the printed workbook opens.
▶ Watch this lessonEn español
Masas de aire y frentes meteorológicos
Grandes volúmenes de aire adquieren la temperatura y la humedad de la región donde se forman: cálidos y húmedos sobre mares tropicales, fríos y secos sobre tierra polar. Cuando dos masas de aire distintas se encuentran, la frontera entre ellas es un frente, y la mezcla ahí produce la mayor parte de nuestro clima cambiante.
Ejemplo: Cuando una masa de aire frío empuja hacia aire cálido y húmedo, el aire frío más pesado se mete por debajo y empuja el aire cálido hacia arriba con rapidez. Ese aire cálido que sube se enfría, su vapor de agua se condensa y se forman las altas nubes de tormenta y los aguaceros repentinos típicos de un frente frío.
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