Barometer

weather · air pressure · science tools

Measures air pressure. A barometer detects how heavy the air pushing down on Earth is at any moment. Different air pressures tell us important things about weather patterns and storms.

Predicts weather changes. When air pressure drops quickly, it often means rain or storms are coming soon. When it rises, fair weather is usually on the way. This makes barometers super useful for short term weather forecasts.

Finds weather systems. Meteorologists use barometer readings to locate pressure systems, cold fronts, and warm fronts that move across regions. These patterns help explain where and how weather will change.

Mercury or aneroid. Old barometers used mercury in a glass tube to measure pressure, but modern ones often use metal boxes that expand and contract. Both types do the same job: they show us how much the air is pressing down.