Lesson 11 of 17
Objective: SWBAT identify weather conditions associated with pressure systems | SWBAT identify and describe how the Coriolis Effect changes the movement of pressure systems
This lesson is very much a continuation of the previous lesson (seen here) and the subsequent lesson (found here) in developing the idea of wind as a function of pressure gradients and unequal heating of Earth's surface. While we won't cover that until tomorrow's lesson, having students understand the theoretical groundwork for convection cells and pressure systems is important to understanding how wind functions as a result of the pressure gradient at Earth's surface. In essence, this lesson focuses on why the pressure gradient exists at all, and how and why some winds move in specific and predictable patterns. In that, this lesson is a fairly straightforward presentation of material - we break down some text and do some practice, in addition to a very brief demonstration.
- Sharpie/Permanent Marker
[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: 5.11 - Pressure Systems (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: 5.11 - Pressure Systems (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)
Students come in silently and complete the (attached) Do Now. In this case, the Do Now is a simple review of material from the previous day on jet streams and prevailing winds. 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:
- It serves as a general review of the previous day's material;
- 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;
- 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,
- 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).
We start off the lesson on the first page of the High and Low Pressure Systems resource by having students independently read an article on high and low pressure systems. The article is one excerpted from USAToday, and is an information rich passage detailing the basics of these pressure systems and how they ultimately connect as large convection cells.
After taking about three (3) minutes to read the article independently, students are asked to summarize the key points of the article in relation to atmospheric movement and pressure systems. On the top of the second page of the High and Low Pressure Systems resource, as a class, we fill in the information that high pressure systems produce more dense, falling air - usually resulting in good weather. The converse is also true; rising, less dense air produces areas of low pressure, usually with poor/inclement weather.
We then read the paragraph at the bottom, which links the information on pressure systems with the previous information covered the previous lesson the Coriolis Effect.
We then jump into a brief demo, which is super simple, and fully explains the Coriolis Effect. Basically, it involves a student volunteer coming up and holding a blown up balloon at the top and bottom. I then make a quick "Equator" about halfway up the balloon, and then ask them to stop turning. Then, I draw a straight line from the Equator to the "North Pole" of the balloon. Then, I ask the student to begin slowly turning the balloon counter-clockwise (from their perspective) and then I draw the same line. When the line is drawn while the balloon is being turned, it creates, instead of a straight line, a line curving to the right. I then indicate that winds, or anything traveling a long distance over the Earth's surface, is subject to the same phenomenon, which we refer to as the Coriolis Effect.
We then look at a picture of some pressure systems imposed on a map of the U.S., with isolines and arrows showing the direction of air movement. We then transition onto the next page of the resource, where we write down what we've observed (Northern hemisphere low-pressure systems curve inward and to the left, while high-pressure systems conversely curve outward and to the right). Figure 21-9 (excerpted from a textbook) shows the relationship between high and low pressure systems as a function of the Earth's rotation.
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.
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
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:
- Do you feel that you mastered the objective for the day?
- Can you reiterate one thing you learned about (in this case, information on high/low pressure systems, 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.