W ARM UP True or False, Explain why you think your answer is correct : Sun bathing on a clear, sunny day without clouds in the sky is more dangerous than sunbathing on a cloudy sunny day. Look at the picture of the clouds. Describe what you see.

O BJECTIVE : SWBAT ANALYZE HOW AIR PRESSURE AFFECTS WIND PATTERNS AND CLOUD FORMATION Agenda: 1.Warm Up 2.Objective 3.Clouds in a Bottle Video 4.Notes 5.Isobar Practice 6.Notes 7.Comprehension Check Video 8.Definition Billboards 9.Exit Ticket

C LOUD IN A BOTTLE VIDEO ANALYSIS 1. What type of liquid does Steve put into the bottle? 2. What does the bicycle pump add to the bottle? 3. What happens when the bicycle pump is released? 4. We see a cloud created when the system goes from _____ pressure to _____ pressure.

A IR PRESSURE Pressure exerted by the weight of air above it. Exerted in ALL directions—down, up, and sideways! Air is pushing down on your desk, but it’s pushing up from below as well, which is why your desk doesn’t collapse. Can change from place to place. Measured in units called millibars.

H OW DOES THIS RELATE TO WEATHER ? Differences in air pressure create winds. Winds change temperature and humidity. So…differences in air pressure cause weather!

R ANDOM A CTIVITY Use a sheet of paper to make a baseball. Be as creative as you would like…Mr. Lambert will be utilizing this tonight during STEM night. You will be limited to 15 minutes to make the ball and cut it out.

P RESSURE CHANGES BECAUSE THE EARTH IS HEATED UNEQUALLY. A IR PRESSURE MAPS : -S HOW ISOBARS -W HAT ARE ISOBARS ? -I SOBARS SHOW PLACES THAT HAVE EQUAL AIR PRESSURE (C LOSER THE ISOBARS THE STEEPER THE PRESSURE AND THE FASTER THE WINDS )

I SOBAR P RACTICE W/ PARTNER ! (20 MINS ) Certain weather maps allow us to view High and Low pressure systems that control the weather. Isobar maps show where pressures are relatively high and low, and show us where pressure changes are gradual or dramatic over a distance.

I SOBAR P RACTICE

Isobars can be used to identify "Highs" and "Lows". The pressure in a high is greater than the surrounding air. The pressure in a low is lower than the surrounding air. 3. Label with an "H" the center of a high-pressure area. 4. Label with an "L" the center of a low-pressure area. I SOBAR P RACTICE

High-pressure regions are usually associated with dry weather because as the air sinks it warms and the moisture evaporates. Low- pressure regions usually bring precipitation because when the air rises it cools and the water vapor condenses. 5. Over which state would you expect to see rain or snow? 6. Over which state would you expect to see clear skies? I SOBAR P RACTICE

In the northern hemisphere the wind blows clockwise around centers of high pressure. The wind blows counterclockwise around lows. It is the opposite in the southern hemisphere. 7. Draw arrows around the "H" on your map to indicate the wind direction. 8. Draw arrows around the "L" on your map to indicate the wind direction. I SOBAR P RACTICE

11. Imagine that you live in New York City. If a Low were approaching you from the west, describe the shift in wind direction as the Low approaches you and then passes to the east. I SOBAR P RACTICE

12. The strength of the wind is determined by changes in the pressure, the pressure gradient. A large change in pressure over a short distance would indicate strong winds. On a weather map, isobars that are close together indicate a strong pressure gradient. Indicate on your map where you expect the strongest winds (the steepest pressure gradient). I SOBAR P RACTICE

F INAL I SOBAR M AP

W HAT IS WIND ? Wind is the horizontal movement of air. It happens because of horizontal differences in air pressure. Wind blows from areas of higher pressure to areas of lower pressure.

T HERE ARE 3 THINGS THAT CONTROL WIND  Pressure Differences  Coriolis Effect  Friction

W HAT IS HUMIDITY ? The amount of water vapor that’s in the air Water vapor is when liquid water turns into a gas through evaporation Air can hold a certain amount of water. The amount of water it can hold depends on temperature Warmer air can hold a lot more water so humidity is higher and the opposite is true

S OMETIMES IN THE MORNING, YOU WALK OUTSIDE AND SEE TINY DROPLETS OF WATER ON EVERYTHING. What is this? Where did it come from?

D EW = CONDENSED WATER VAPOR. If air gets cool enough, it can condense to form small drops of water. Dew point = the temperature at which water vapor will condense So, when the air gets cool enough, the water vapor turns into liquid. Does this sound like something else that happens in the atmosphere?

C LOUDS … 1. As you go higher in the atmosphere there is less pressure. 2. Air then expands and cools (dry adiabatic rate) 3. When it cools down enough, it reaches its dew point 4. Once it hits the dew point, it becomes a cloud!

3 THINGS NEEDED TO MAKE A CLOUD : Water vapor/humidity Temperature difference Condensation nuclei: tiny particles for water to condense around

C OMPREHENSION C HECK V IDEO HTTP :// WWW. YOUTUBE. COM / WATCH ? V =I0C4QR0OEH0 HTTP :// WWW. YOUTUBE. COM / WATCH ? V =I0C4QR0OEH0 1. We can measure atmospheric pressure with a device called a ____________________. It is a way of measuring the weight of air. 2. The weight of air is referred to as ____________________________. 3. Air pressure is measured in units called ______________________. 4. What happens when the block on the left is heated up? 5. What happens when air is chilled? 6. Air pressure helps determine the ____________________. 7. The boundaries between high pressure systems and low pressure areas can be ______________________. 8. Wind is caused by the movement of air from a ____________ pressure to a _____________ pressure area.

E XIT T ICKET 1. What happens at the dew point? 2. In which direction is air pressure exerted? 3. What are the forces that influence wind? 4. What kinds of wind occur where isobars are far apart? 5. What causes air to rise?