Aim: What are the various properties of gases?

Do Now: 1. How would you prove that gases are matter?

2. Define -compressible-elastic-diffusion-air pressure

Aim: What are the various properties of gases?

• Gases take up space because…

• Gases are a form of matter and matter takes up space

Aim: What are the various properties of gases?

• Gases are compressible

Aim: What are the various properties of gases?

• Gases diffuse rapidly

Aim: What are the various properties of gases?

• Gases fill their container completely

Aim: What are the various properties of gases?

• Gases exert pressure

Aim: What are the various properties of gases?

• Barometers measure air pressure

Aim: What are the various properties of gases?

Essential Questions:• Explain how a mercury barometer works.• How are the units of pressure related to each

other?• Why would you rather have a person wearing

shoes step on your hand than a person wearing ice skates? Explain in terms of pressure.

• Explain illustration on handout comparing air pressure at sea level and atop Mt. Everest.

• The History of the Barometer• Evangelista Torricelli invented the mercurial barometer

• Barometer - Pronunciation: [b u rom´ u t u r] - a barometer is an instrument for measuring atmospheric pressure. Two common types are the aneroid barometer and the mercurial barometer (invented first). Evangelista Torricelli invented the first barometer, known as the "Torricelli's tube".

• Biography - Evangelista Torricelli• Evangelista Torricelli was born October 15, 1608, in Faenza, Italy and died October 22, 1647 in Florence, Italy. He was a physicist and

mathematician. In 1641, Evangelista Torricelli moved to Florence to assist the astronomer Galileo. • The Barometer• It was Galileo that suggested Evangelista Torricelli use mercury in his vacuum experiments. Torricelli filled a four-foot long glass tube

with mercury and inverted the tube into a dish. Some of the mercury did not escape from the tube and Torricelli observed the vacuum that was created. Evangelista Torricelli became the first scientist to create a sustained vacuum and to discover the principle of a barometer. Torricelli realized that the variation of the height of the mercury from day to day was caused by changes in the atmospheric pressure. Torricelli built the first mercury barometer around 1644.

• Evangelista Torricelli - Other Research• Evangelista Torricelli also wrote on the quadrature of the cycloid and conics, the rectifications of the logarithmic spiral, the theory of

the barometer, the value of gravity found by observing the motion of two weights connected by a string passing over a fixed pulley, the theory of projectiles and the motion of fluids. Lucien Vidie - Aneroid Barometer

• In 1843, the French scientist Lucien Vidie invented the aneroid barometer. A aneroid barometer "registers the change in the shape of an evacuated metal cell to measure variations on the atmospheric pressure." Aneriod means fluidless, no liquids are used, the metal cell is usually made of phosphor bronze or beryllium copper.

• Related Instruments• An altimeter is an aneroid barometer that measures altitude. Meteorologists use an altimeter that measures the altitude with respect

to sea level pressure. A barograph is an aneroid barometer that gives a continuous reading of atmospheric pressures on graph paper.