Barometers can be of two types: mercury barometers and aneroid barometers.
The standard atmospheric pressure at sea level is 760 mmHg or 1 atm.
Barometric pressure readings are essential for calculations involving the Ideal Gas Law, $PV = nRT$.
Changes in barometric pressure can indicate weather changes; a falling barometer suggests stormy weather, while a rising one indicates fair conditions.
Torricelli invented the mercury barometer in 1643, which led to the discovery that air has weight.
Review Questions
What are the two main types of barometers?
How does a falling barometer reading affect weather predictions?
What is the standard atmospheric pressure at sea level in mmHg?
Related terms
Atmospheric Pressure: The force exerted by the weight of the atmosphere above a surface area.
Ideal Gas Law: $PV = nRT$, where P is pressure, V is volume, n is moles of gas, R is the gas constant, and T is temperature.
Mercury Barometer: A type of barometer that uses mercury to measure atmospheric pressure.