The Atmosphere and Air Pressure
Lesson 9 of 14
Objective: SWBAT identify the layers of the atmosphere and describe how the pressure applied by the air in the troposphere affects weather.
The Why Behind Teaching This
Unit 5 covers standards relating to Earth's Systems. It covers Standard 5-ESS2-1: Develop a model using an example to describe ways the geosphere, biosphere, hydrosphere, and/or atmosphere interact. Students will be learning the difference between each of the systems, and ways that each of the systems interact to help make Earth what it is today. The other standard covered is Standard 5-ESS2-2: Describe and graph the amounts and percentages of water and fresh water in various reservoirs to provide evidence about the distribution of water on Earth.
Modeling will be an important component of this unit. Students will be modeling layers of Earth, the water cycle, land forms, and more. The unit begins with an overview of all the systems, then each system is taught in isolation. As each new system is covered, how it depends on or interacts with the previous systems will be addressed. In addition to the end of unit assessment, there will also be a culminating activity where groups build a model to demonstrate how 2 of the systems interact. Connections to several previously covered standards will also be made throughout this unit.
This specific lesson covers standard 5-ESS2-1 by introducing students to what the atmosphere is. It also begins to develop the foundation for how the atmosphere interacts with the hydrosphere by identifying how high pressure and low pressure affect the water cycle. An introduction to the ozone layer was also made which begins to build background knowledge about how the atmosphere impacts the biosphere.
The goal of today's lesson is for students to be able to identify the layers of the atmosphere, and identify which layer weather occurs in and where the ozone layer is located. After this lesson they should also be able to describe how low pressure and high pressure in the atmosphere affect weather.
Students will demonstrate success on this lesson goal by correctly answering 100% of the questions on the exit ticket correctly.
Preparing For The Lesson:
- A copy of the Items in the Atmosphere cards for each group.
- A copy of the Layers of the Atmosphere Foldable for each group that has been precut on the dotted lines for each student
- Computer and overhead to show the video
- 20 gallon sized Ziplock bags that have a straw stuck in them, sealed around the straw, and then taped to cover any holes. Insert picture of a completed bag
- 5 dictionaries or other large books to lift with air
- 2 desks to lift with air
- 2 large tables to lift with air
- copy paper for each group for their poster
What Do These Items Have in Common?
I provide each group with a set of Items in the Atmosphere cards. I ask the groups to determine what the items on the cards have in common. There is a satellite, airplane, meteor, rain cloud, tornado, and hot air balloon. One group suggested that the items all have or use energy. Another group suggested that they are all in the air. Another group said that they all involve science in same way. All of their answers are valid and have science reasoning behind them which I was happy to see.
I connect the pictures they are looking at to today's lesson by telling students; all of the items you are looking at are in the sky or travel through the sky. The air, or sky, that surrounds Earth is called the atmosphere. The atmosphere is what makes it possible for life to survive on Earth.
What is the Atmosphere
I provide each student with a copy of the Layers of the Atmosphere Foldable that I have precut along the dotted lines to save time. Each ring represents a new layer and folds over to reveal an area where we will record some information. I play the video below and pause it when each layer name is revealed so I know students have time to copy it down. I remind students that the goal of this unit is for them to be able to model how Earth's systems interact, so they should be watching for ways the atmosphere might impact other systems as they watch the video. I remind them of the posters around the room that they can add information to as we learn about the atmosphere. We discuss the video and record facts after it is finished.
After watching the video, I place a copy of the foldable on the overhead for students to use as an example as we record information. I ask students for some facts about the Troposhere. They tell me that it is about 7 miles thick and that it is where weather occurs. I record this information under the troposphere flap and allow time for them to copy.
I then ask students for some facts about the Stratosphere. Students tell me that this is where planes fly and there are strong winds called the jet stream that helps them go faster. Another fact they are able to tell me is that the ozone layer is found in this layer. When asked what the ozone layer is, the students tell me that it helps block harmful UV rays. I add this information into the foldable under the flap for Stratosphere and allow time for students to copy.
Our next layer is the Mesosphere. I ask students what they remember about this layer. Students tell me that this is the coldest layer and that this is also where meteoroids burn up as they enter the atmosphere. We have a discussion about what a meteoroid is and what causes it to burn up.
The final layer is the Thermosphere which is the largest layer. Students tell me that this layer is the hottest because of the UV light turning into heat. Students also tell me that this is where auroras can be seen.
How Strong is Air Pressure
How strong do you think air is? Strong enough to lift 5 dictionaries? I hold up a gallon size Ziplock bag with a straw sticking out of. If I blow air into this bag, do you think the air will be strong enough to lift these 5 dictionaries? Some of the students say yes, some say no. I place the bag under the books so that the end with the straw sticks out. I blow in the straw to fill the bag with air and the books rise.
Do you think it would be strong enough to lift a desk? Again, some students say yes and others say no. I place 4, gallon size Ziplock bags on top of a desk and then flip another desk over so that the top flat surface is on top of the bags. I select 4 students to come up and fill the bags with air. I count to three so they all start blowing at the same time. If they do not start at the same time it gets off balance very quickly. As you can see in the video of students using air to lift a desk, the students fill the bags and the desk on top lifts up easily.
So 4 bags of air will lift a desk, do you think 12 bags would be strong enough to lift a table? Most students say yes. At this point I think most students are just amazed and think it could lift anything. I place 12 gallon size Ziplock bags with straws sticking out around one large rectangle table. I have a couple of students take our other rectangle table that is the same size as the first one and help me flip it over on top of the bags . I select 12 students to come up and fill the bags with air. When I count to three, they all begin blowing, and the table goes up. I always stand right beside the table in case it starts to get unbalanced and ready to slide off. As you can see from the video of students using air to lift a table, it was very easy for the group of 12 to lift the table. The students are always amazed that just air can lift the table so easily.
How Air Pressure Affects the Water Cycle
I explain to students: when there is a high pressure system in the atmosphere that means that the air is pressing down a lot. When there is a low pressure system in the atmosphere the air is not pressing down a lot. I want you to look back at your water cycle diagram that we created (water cycle lesson previously taught). How would a high pressure system and low pressure system affect the water cycle? You are going to think about this with your group and create a poster showing what the weather would be like if there was a high pressure system and what it would be like if there were a low pressure system. I want your poster to include what it would look like outside, will it be sunny or cloudy? What items would you leave the house with in each case?
I place my water cycle diagram on the overhead and use my hand to model high pressure. I tell groups to think about how this air pressing down might affect the water that has evaporated. Then I raise my hand up higher in the sky of the drawing and say, now there is low pressure and the air is not pressing down. How would that affect the water that has evaporated. I want to see if they are able to reason through how these different air pressure systems will affect the weather without me telling them the impact.
I provide each group with a piece of copy paper. I tell them to divide the paper in half and label one side, High Pressure, and the other side Low Pressure. As they begin reviewing their water cycle diagram and discussing how the air pressing down affects it, I circulate to answer questions.
Most groups drew an accurate poster. I was looking for the low pressure side to show clouds and rain, and the high pressure side to show clear, sunny skies. 5 out of 7 groups that did this created accurate posters. A couple of these examples are below. Because a high pressure system traps the water vapor low in the atmosphere it does not travel up and thus does not cool and condense to form clouds. If there is low pressure the water vapor travels up through the atmosphere and condenses to form clouds.
The two groups that did not get it correct had the two sides switched. They showed clear skies on low pressure, and rain on high pressure. I was glad that there were a couple of errors so that it allowed for an opportunity to review. As soon as the first group presented and we reviewed the other group wanted to change their poster. I of course did not allow that, I had them present last so that it allowed for an opportunity to review and reinforce again at the end. I think getting it wrong, and seeing the other 5 correct posters will really help the students who were struggling remember the content in the future. The two incorrect posters are below.
After groups present, I provide each student with an Atmosphere and Air Pressure Exit Ticket. The exit ticket assesses their understanding of the layers of the atmosphere, as well as how high pressure and low pressure affect weather. After I pass out the exit ticket, I provide the ESE/ELL students with a copy of the Layers of the Atmosphere Names (not in order), to use as a reference. I do not expect these students to have the names of the layers memorized yet. As we review them daily, they should be able to remember them by the time they take the assessment.
Results from Exit Ticket
I grade the exit tickets later. I separate them into three piles, those who got them all correct, those who missed only one or two, and those who missed more than two. I found that only 3 out of 20 students got perfect scores. 2 of those examples are below.
The majority of students missed 2. 10 out of the remaining 17 fell into this category. I was happy to see though that only 2 of those were due to the high pressure and low pressure comparison at the bottom of the exit ticket. This was something that a couple of groups mixed up on the posters earlier in the lesson. We reviewed and they had the opportunity to see the correct answer several times which I think helped them remember the difference for the exit ticket.
The remaining 7 students fell into the -3 or more category. This group ranged from missing just 3, to not answering any. Some students mixed up a couple on the top, which usually then led to them missing the first couple of questions at the bottom as well. Some students ran out of time and had to leave a few blank as well. For those that had blanks, I will call them over individually during math stations to check understanding verbally. This will help me get a better idea of what they know. Since such as large number fell into the -3 or more category, I will be sending home homework as an opportunity to practice this concept more.