Bellwork

1) Name all the steps of the water cycle. 2) How does water from the ocean turn

into a cloud? What are the steps?

Objective for the day

By the end of the day…

SWBAT describe heat transfer and air pressure in the atmosphere.

Convection Currents Review

Density goes down

Density goes up

Heat transfer in the troposphere

Key Point #1: Radiation, conduction, and convection work together to heat the troposphere.

Radiation: heat transfer through empty space Conduction: heat transfer through direct contact Convection: heat transfer through a fluid (liquid or

gas)

Key Point #1: Radiation, conduction, and convection work together to heat the troposphere.

Radiation: heat transfer through empty space Conduction: heat transfer through direct contact Convection: heat transfer through a fluid (liquid or

gas)

Heat Transfer in the Troposphere

Where do you find radiation in the atmosphere? From the sun

Where do you find conduction? The sun heats the ground, which then heats the

air.

Where do you find radiation in the atmosphere? From the sun

Where do you find conduction? The sun heats the ground, which then heats the

air.

Questions

Where do you find radiation in the atmosphere? From the sun

Where do you find conduction? The sun heats the ground, which then heats the air.

Where do you find convection? When the air is heated from the ground, the

molecules start a convection current in the air. Convection causes most of the heating in the troposphere.

Where do you find radiation in the atmosphere? From the sun

Where do you find conduction? The sun heats the ground, which then heats the air.

Where do you find convection? When the air is heated from the ground, the

molecules start a convection current in the air. Convection causes most of the heating in the troposphere.

Properties of Air

Air has mass.

Key Point #2: Because air has mass, it also has other properties, including density and pressure.

Air has mass.

Key Point #2: Because air has mass, it also has other properties, including density and pressure.

Mass is often given in grams (g) Volume is often given in milliliters (mL)

Therefore, density is given in grams/milliliters (g/mL)

Mass is often given in grams (g) Volume is often given in milliliters (mL)

Therefore, density is given in grams/milliliters (g/mL)

#1 Practice:What is the density if the m=10g and

v=2mL?

#2 Practice:What is the volume if the d=2g/mL and

m=6g?

#3 Practice:What is the mass if density=4 g/mL and

v=2 g/mL?

Pressure

The force pushing on an area or surface is known as pressure.

Key Point #3: Air pressure at a certain point is the amount of weight of a column of air pushing down at that point.

The force pushing on an area or surface is known as pressure.

Key Point #3: Air pressure at a certain point is the amount of weight of a column of air pushing down at that point.

Pressure

Denser air exerts more pressure than less dense air.

Denser air exerts more pressure than less dense air.

Denser air = MORE air pressure

Less dense air = LESS pressure

Denser air = MORE air pressure

Less dense air = LESS pressure

Think-Pair-Share

What is the relationship between the temperature of air and how much pressure it has? Hotter air has a LESS air pressure. Cooler air has MORE air pressure.

Denser air = MORE air pressure

Less dense air = LESS pressure

Denser air = MORE air pressure

Less dense air = LESS pressure

Temperature/Density/Pressure

HOT air = Density = Pressure

COOL air = Density = Pressure

If Density goes down, Pressure goes down. If Density goes up, Pressure goes up.

Measuring Air Pressure

Air pressure is often measured in millibars, just like weight is often measured in pounds.

Air pressure is often measured in millibars, just like weight is often measured in pounds.

Increasing Altitude

Key Point #4: The higher you are, the lower the air pressure is.

Air pressure is greatest as sea-level. Why?

Sea-level air has the weight of the whole atmosphere pressing on it.

Key Point #4: The higher you are, the lower the air pressure is.

Air pressure is greatest as sea-level. Why?

Sea-level air has the weight of the whole atmosphere pressing on it.

Think-Pair-Share

Look back at your Key Point #3. Now how does altitude relate to density?

Increasing altitude decreases density.

Which has the greatest air pressure?

Which has the least air pressure?

Which has the greatest density?

Which has the least density?

A

B

C

Exit Ticket

1. Describe what air pressure at a certain point means. (Think of the stack of books)

2. Does denser air have more or less air pressure? Explain.

3. If air in California near the shore is 80 °F, and air in Florida near the shore is 88 °F, which state has the greater air pressure? Explain your reasoning.