Science · 6 pages · 12 min
How a barometer reads the weight of air
A mercury column, or a sealed metal capsule, stands where the air's weight balances it.
When the purchase is complete, return to the original window. It will refresh.
From the opening
A barometer reads the weight of the air by letting that weight balance something you can see move. In the classic instrument a column of mercury stands only as high as the atmosphere can hold up, with a vacuum above the mercury. The opening covers the mercury column Torricelli stood up, why the space above is empty, and the aneroid capsule and its needle.
The rest of the brief — the later sections and the reading notes — opens after Stripe confirms payment.
Inside
- The mercury column Torricelli stood up
- Why the space above is empty
- The aneroid capsule and its needle
- Altitude and weather on one dial
- Where the idea stops applying
- A distinction worth keeping
Sources
- Torricelli's mercury barometer
- Aneroid capsules as mechanical barometers