Study Guides/Physics/Aneroid Barometer: Working and Uses
Study Guide · Physics

What is an Aneroid Barometer?

A barometer is a scientific instrument used to measure atmospheric air pressure. While traditional barometers use a glass tube filled with toxic liquid mercury, the Aneroid Barometer measures pressure without using any liquid at all (the word 'aneroid' means 'without liquid').

Question (Click to Flip)

Why is an aneroid barometer better than a mercury barometer?

Answer

Aneroid barometers are smaller, less fragile, do not spill, and contain no toxic mercury, making them much easier to transport and use safely.

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Key Facts

Invented by French scientist Lucien Vidi in 1844.

'Aneroid' comes from Greek words meaning 'not wet'.

High pressure usually brings clear, sunny weather.

1. How Does it Work?

Inside the barometer is a small, flexible metal box called an aneroid cell (or capsule).

  • This capsule is partially evacuated (air is sucked out) and sealed.
  • When atmospheric pressure increases, it presses down on the flexible box, causing it to contract.
  • When atmospheric pressure decreases, the box expands outward.
  • This tiny movement is amplified by a system of mechanical levers and springs, which moves a needle on the dial face to indicate the pressure.

2. Uses and Advantages

  • Weather Forecasting: Changes in air pressure help meteorologists predict weather (e.g., dropping pressure indicates a coming storm).
  • Altimeters: Since air pressure drops at higher altitudes, aneroid barometers are used in airplanes to measure altitude.
  • Advantage: They are highly portable, safe (no toxic mercury), and durable, making them ideal for ships and aircraft.

Questions and Answers

Why is an aneroid barometer better than a mercury barometer?+

Aneroid barometers are smaller, less fragile, do not spill, and contain no toxic mercury, making them much easier to transport and use safely.

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