Bell Ringer 10-27-14

• Be sure to put the date on the outside of the page!• Copy down the question below and answer it.

1. What is the composition of air?

2. Does air weigh anything?

3. Is air heated evenly across the Earth?

• Conclusion Questions: You MUST CSRQ1. What was the pressure like inside the jar when hot water was

added? 2. What was the pressure like inside the jar when cold water was

added?3. How did we change the conditions of the air inside the jar? 4. What is a barometer? (pg. 12 in the weather textbook)5. If you took your homemade barometer high up on the top of a

mountain (example: in Colorado about 10,000 feet) would your barometer show lower pressure or higher pressure? (pg. 13 & 14 in textbook)

6. If you took your barometer to sea level, would your barometer show higher or lower pressure? (pg. 13 & 14 in book)

7. Why is it harder to breath at the top of the mountain in Colorado? Use the term density to explain your answer. (pg. 15 of your text). You may use the back of this paper if you need more room.

The Atmosphere

Air Pressure

The Atmosphere - Air Pressure

Air Pressure

The weight of the column of air that is

above you.

The Atmosphere

Cooler, More Dense

Air Sinks

Warmer, Less Dense

Air Rises

Low Pressure

HighPressure

Ground is heated by radiation

Upper Troposphere is Cold

The Atmosphere - Air Pressure

Measuring Air Pressure

Barometer – a device to measure air pressure.

The Atmosphere - Air Pressure

Measuring Air PressureAir pressure pushes down on the surface of the mercury in the dish, causing the mercury in the tube to rise. The air pressure is greater on the barometer on the right, so the mercury is higher in the tube.

Mercury Barometer – a device to measure air pressure in inches of mercury (in.)

The Atmosphere - Air Pressure

Measuring Air Pressure

This diagram shows an aneroid barometer. Changes in air pressure cause the walls of the airtight metal chamber to flex in and out. The needle on the dial indicates the air pressure.

Aneroid Barometer – measures air pressure in milibars (mb)

The Atmosphere - Air Pressure

Altitude and Density

The density of air decreases as altitude increases. Air at sea level has more gas molecules in each cubic meter than air at the top of a mountain.

The Atmosphere - Air Pressure

Air Pressure and Altitude

Air pressure decreases as altitude increases.

The Atmosphere

How does Air Pressure affect the Weather?

• High pressure will be shown as an H on a weather map

• A high pressure system will bring clear, cooler, dry air.

• Air spins clockwise around a H

The Atmosphere

How does Air Pressure effect the Weather?

• Low Pressure will be shown as a L on a weather map

• Lows bring cloudy conditions with a chance of precipitation

• Air spins counter-clockwise around a L

The Atmosphere

Graphic Organizer

increases

Air Pressure

decreasesas

measured in units of

measured with

Density decreases

Altitude

Millibars

Aneroid

include

Inches of mercury

Barometers

Mercury