Functional Analysis What is the meaning of a barometer? _______________________________________________________________________________________________________________________________________________________________________________________________________

Nom : Date : Measuring the pressure

Barometer

Course Note : 1^ère– T^ale

Page 1on3 In space, there is a nearly complete vacuum so the air pressure is zero. On

Earth, because there are many miles of air molecules stacked up and exerting pressure due to the force of gravity, the pressure is about 14.7 pounds per square inch at sea level.

You should know that hot air is less dense (lighter) than cooler air.

These pressure differences have a big effect on the weather, so if you know the current air pressure at your house, as well as the pressure trend, you are able to

predict certain things about the weather. As a very loose rule, a high-pressure area will be clear, and a low-pressure area will be cloudy and rainy.

Functional Analysis

What is the meaning of a barometer?

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A barometer measures air pressure:

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A "rising" barometer indicates:

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A "falling" barometer indicates:

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Nom : Date : Measuring the pressure

Barometer

Course Note : 1^ère– T^ale

Page 2on3 Glossary:

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By listening the video from start to 0’43’’, fill the glossary below

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Listen to the video and answer the following questions:

What is a capsule?

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What is the purpose of the capsule?

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What is the behaviour of the capsule in reaction of the pressure?

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Why is there a L shaped lever between the gear system and the capsule?

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Nom : Date : Measuring the pressure

Barometer

Course Note : 1^ère– T^ale

Page 3on3

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Complete the following sentences

Even a mass of ___________in air ____________ only makes that capsule moves by a ______________ of an inch. The barometer is designed to _____________ that range of motion by _______________ it more than ______________

times. The _____________ and the ______________ each do their part to magnify that range of motion. First the L

shaped lever. It has a ________________ section that rest on the capsule ________________ a longer section locks into

a_________________ shaped gear. Because this greater the length it’s almost ______________ the capsule’s range of

motion and the lever ________________ the capsule’s __________________________ into a

_________________________________. Because the lever ________________ the gear very close to the gear axis of

rotation, it multiplies that motion up to ____________________________ more and rotates the gear. Now, as that gear

rotates its teeth lock in and engage with the teeth on the second gear _______________ like a _______________. That

wheel shaped gear has a very small _________________ which as it rotates multiplies the motion another

_______________ times and moves the ________________ arm.