 How do air pressure and temperature vary in the atmosphere? Big Idea

Air Pressure Chapter 7, Section 2

Learning Goals What kinds of questions can you ask?

Learning Goals

 SWBAT list some of the properties of air  SWBAT list and describe what instruments are used to measure air pressure  SWBAT explain how increasing altitude affects air pressure and density Learning Goals

density The amount of mass in a given volume of air. Density equals mass divided by volume.

pressure Air is all around us. Just like water pressure increases as you go deeper underwater, air pressure will decrease the higher up in altitude you go. Pressure is the force pushing on an area or surface.

Air pressure Air pressure is the result of the weight of a column of air pushing down on an area.

barometer A barometer is an instrument that is used to measure air pressure.

Mercury barometer Consists of a glass tube open at the bottom end and partially filled with mercury. Mercury is a silvery- white metal that is liquid at room temperature. It is poisonous to humans and animals.

Aneroid barometer “Aneroid” means “without liquid.” An aneroid barometer has a metal chamber that is sensitive to changes in air pressure. Why would there be images of the weather on an aneroid barometer?

Altitude The distance above sea level, which is the average level of the surface of the oceans.

Altitude The distance above sea level, which is the average level of the surface of the oceans.

 Density = Mass/Volume  The more molecules in a given volume, the greater the density. Properties of Air

 Pressure – air has weight! Properties of Air Because air has mass, it also has other properties, including density and pressure.

Measuring Air Pressure Two kinds of barometers are mercury barometers and aneroid barometers.

Altitude and Air Pressure What story does this picture tell? Air pressure decreases as altitude increases. As air pressure decreases, so does density.

 What are some of the properties of air? Key Questions

 What are some of the properties of air?  Because air has mass, it also has other properties, including density and pressure. Key Questions

 What are some of the properties of air?  Because air has mass, it also has other properties, including density and pressure.  What instruments are used to measure air pressure? Key Questions

 What are some of the properties of air?  Because air has mass, it also has other properties, including density and pressure.  What instruments are used to measure air pressure?  Two kinds of barometers are mercury barometers and aneroid barometers Key Questions

 What are some of the properties of air?  Because air has mass, it also has other properties, including density and pressure.  What instruments are used to measure air pressure?  Two kinds of barometers are mercury barometers and aneroid barometers  How does increasing altitude affect air pressure and density? Key Questions

 What are some of the properties of air?  Because air has mass, it also has other properties, including density and pressure.  What instruments are used to measure air pressure?  Two kinds of barometers are mercury barometers and aneroid barometers  How does increasing altitude affect air pressure and density?  Air pressure decreases as altitude increases. As air pressure decreases, so does density. Key Questions

 Science Workbook Chapter 7 Section 2, pg Homeowork