Air Masses

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Objective

SWBAT define an air mass and identify the five (5) major types of air masses, including where they originate

Big Idea

In this lesson, students identify the type and origin of the five major air masses that impact the United States

Lesson Introduction

In this lesson, students have the opportunity to learn about air masses and how source regions are an important part of atmospheric weather. They learn what air masses are, where they come from, and how they're named and characterized. They then do some simple weather analysis with the help of their Earth Science Reference Tables [ESRT] before jumping into some practice and the associated exit ticket for the day. Like many atmospheric/weather information-based lessons, this is image and technology heavy, as this allows students to most easily visualize the phenomenon occurring. This material is also going to be necessary when students start studying fronts (lessons here and here) over the next few days. There are no special materials or resources needed with this lesson. 

[Note: For embedded comments, checks for understanding (CFUs), and key additional information on transitions and key parts of the lesson not necessarily included in the below narrative, please go to the comments in the following document: 5.14 - Air Masses (Whole Lesson w/comments). Additionally, if you would like all of the resources together in a PDF document, that can be accessed as a complete resource here: 5.14 - Air Masses (Whole Lesson)[PDF]. Finally, students may need their Earth Science Reference Tables [ESRT] for parts of the lesson (a document used widely in the New York State Earth Science Regents course) as well.]

Do Now & Objective(s)

10 minutes

Students come in silently and complete the (attached) Do Now. In this case, the Do Now is a review of some really tough standards from Unit 4 (Insolation) and a question about pressure systems and air movement from a few lessons ago. After time expires (anywhere from 2-4 minutes depending on the type of Do Now and number of questions), we collectively go over the responses (usually involving a series of cold calls and/or volunteers), before I call on a student and ask them to read the objective out loud to start the lesson.

As a general note, the Do Now serves a few purposes:

  1. It serves as a general review of the previous day's material; 
  2. It is a re-activation of student knowledge to get them back into "student mode" and get them thinking about science after transitioning from another content area or alternate class;
  3. as a strategy for reviewing material students have struggled with (for example, using this as a focused review for material that they have struggled with on unit assessments or recent quizzes); and,
  4. It is an efficient and established routine for entering the classroom that is repeated each day with fidelity (I never let students enter the classroom talking. While it may seem potentially severe to have students enter silently each day, this is both a school wide expectation and a key component of my classroom. In many respects, I find that students readily enjoy the focus that starting with a quiet classrooms brings each day).

Air Masses

25 minutes

Just for context, I start the lesson with a question: "Do you know how blizzards form?" When I taught this for the 2014-2015 school year, we had coincidentally just come back from a school cancellation as a result of an impending blizzard, so this lesson was of particular relevance. I take a few brave responses, but basically, winter storms form when air masses join together and produce a lot of energy - which I indicate will be the focus of today's lesson.

On the first page of the Air Masses resource, students break down a text that has relevant information on air masses, source regions, and their characteristics (temperature and humidity). I have the students read the information together, answer the "Stop & Jot" (in the resource, "S+J" is short for "Stop & Jot") question, and then complete the passage by determining the airmass characteristics. For example:

Humidity: Classified as maritime (humid) or continental (dry)

Temperature: Classified as polar (cold), arctic (very cold), or tropical (warm)

On the Notes section on the second page of the Air Masses resource, students assemble those notes by briefly filling in the table at the top of the page. On the bottom table, they are tasked with using the associated images on the next page, in addition to their notes (the air mass names are also listed on Page 13 of their Earth Science Reference Tables [ESRT]), to fill in the required information on the air mass name, characteristics, and source region (as a logistical note, this work is also done with their desk/table partners).

Practice

20 minutes

The Practice section in this lesson is, like the vast majority of questions found in all of my classwork and homework, is 100% Regents-based. All of the questions come from prior Regents examinations. Likewise, as I try to generally do with all of my lessons, the questions are mostly organized to get increasingly more difficult and increase in complexity, which is why the harder questions tend to come toward the end. For whatever reason, the Regents loves to ask questions about source regions and air masses, so I truly think the practice is worthwhile, considering this is something they'll see over and over and over again in the future. In terms of air masses, this is content that is usually "bundled up" with other content from other lessons (i.e. this lesson on the prevailing winds or the next day's lesson on fronts), so it's important that students are able to get at this materially contextually. Most of the practice questions they'll see, while from the Regents, are attempts to isolate just the information on air masses. The greater practice and automaticity they build with this, the more equipped they'll be to tackle those tougher questions down the road. 

In terms of student work habits, I tend to sometimes make this decision in the moment, and as a response of what I know about the students and how they're processing the material on, but I'll either ask them to work independently, in partners, or (sometimes) give them the option. Usually, before starting practice, we tend to go over some steps for self-help ("What should you do if you're stuck?"), and I might reference a previously used multiple-choice or free response strategy in order to build their skills while simultaneously learning content (as an example - one popular one we always use - "If you aren't sure what the right answer is, see if you can eliminate some wrong answer choices"). I tend to circulate for compliance and then hone in on specific students while they're doing this. 

After about 10 minutes, we go over their responses. Students who finish early are encouraged to work on the exit ticket (resource below) and double-check their responses. We use a combination of strategies (active voting, cold calling, popsicle sticks, volunteers) to go over the responses, where students correct their work and ask any clarifying questions. 

Exit Ticket & Closing

5 minutes

In the last few minutes of class, I have students complete the daily Exit Ticket. For the sake of time, I have students grade them communally, with a key emphasis on particular questions and items that hit on the key ideas of the lesson (Note: This usually manifests as students self-grading, or having students do a "trade and grade" with their table partners). After students grade their exit tickets, they usually pass them in (so that I can analyze them) and track their exit ticket scores on a unit Exit Ticket Tracker. 

After students take a few seconds to track their scores, we usually wrap up in a similar way. I give students time to pack up their belongings, and I end the class at the objective, which is posted on the whiteboard, and ask students two questions:

  1. Do you feel that you mastered the objective for the day?
  2. Can you reiterate one thing you learned about (in this case, information on air masses, their characteristics and source regions, etc.)?

Once I take 2-3 individual responses (sometimes I'll ask for a binary "thumbs up/thumbs down" or something similar), I have students leave once the bell rings.