L.O: students will be able to describe air temperature and air pressure Do Now: Answer the Regents questions AND open your reference tables to page 13!

Temperature Temperature is the measure of the average kinetic energy of particles. (how hot or cold something is) Heating of the atmosphere is caused by the incoming solar radiation to the Earth. The more insolation an area has the higher the temperature. We measure the air temperature using a thermometer in Celsius, Fahrenheit Or Kelvin

What do you notice about these air temperatures?

Air temperature changes tend to be cyclically Cold in morning, then hot in the afternoon. Cold at night and then warm in the day

Seasonal air temperature changes are also cyclical Seasonal air temperature changes are also cyclical. Cold in winter, then hot in summer. Over and over ….

What happens to air temp as altitude increases? in troposphere : Air Temperature decreases, then in stratosphere temperature increases then in the mesosphere it decreases, then in the thermosphere temperature increases a lot. L.O. SWBAT explain properties of the atmosphere

We model temperatures on weather maps by drawing isotherms.

Isotherms: lines connecting points with equal temperatures.

Based on the map, state the relationship between latitude and temperature.

As latitude increases, temperature decreases. High latitude, Low temp Low latitude, High temp

Air Pressure Air Pressure – the weight of the atmosphere per unit area. The force of the air pushing down on the earth. Air pressure is also called barometric pressure.

How do we measure air pressure? Barometer – this is the instrument used to measure air pressure. UNITS: Millibars (mb) Inches of Mercury (in. Hg) Barograph: A graph showing the change in pressure over time. use ESRT page 13 to convert Millibars (mb) to inches of mercury

Isobars: lines connecting points with equal air pressure. These lines are called isobars

3 Factors that affect atmospheric pressure Altitude temperature humidity

As altitude increases, air pressure decreases because the air is less dense thinner

Temperature vs. Air Pressure Warm air is less dense than cold air. As a result, warm air has a lower pressure than cold air. Cold air being denser would have higher pressure. H L Cold, more dense air Warm, less dense air

Humidity: The amount of moisture in the air. A psychrometer is used to measure humidity.

Moisture vs. Air Pressure Moist air is less dense than dry air. As a result, moist air has a lower pressure than dry air. Dry air being denser would have higher pressure. H L Dry, more dense air Moist, less dense air

Why is moist air less dense than dry air? Answer: Water Vapor is a lighter gas than Nitrogen and Oxygen Dry Air Gas Atomic Mass N2 (78%) 28 amu O2 (21%) 32 amu Moist Air Gas Atomic Mass N2 (76%) 28 amu O2 (20%) 32 amu H2Ov (3%) 18 amu