Apparent Motion of the Sun

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Objective

SWBAT diagram the path of the Sun in New York during the spring/autumn equinox and spring/summer solstice on an altitude diagram [Apparent motion]

Big Idea

Students analyze and create altitude diagrams, or images of the Sun's path at specific times of the year, in this challenging and engaging lesson

Lesson Introduction

[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: 4.3 - Apparent Motion of Sun (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: 4.3 - Apparent Motion of Sun (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.]

I truly feel that this lesson is particularly challenging for students. I've taught this more than once, and for whatever reason, I find that this content is somehow hard to grasp for many students. In effect, they use altitude diagrams, which are images in which one can chart and see the path of the Sun on particular days of the year, and at particular latitudes on Earth's surface. For example, you can make an altitude diagram for the Summer Solstice in New York State, in which the Sun reaches a maximum height in the sky of about 42 degrees. In this lesson, students first analyze, and then create their own altitude diagrams in NYS, and at other latitudes, during the key solstices and equinoxes during the solar calendar. 

Do Now & Objective

10 minutes

Students come in silently and complete the (attached) Do Now. This Do Now consists of a general review around the radioactivity and half-life, in addition to having a quick review question from the previous day (#3). 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).

Altitude Diagrams I

20 minutes

[Note: Please refer to the embedded comments in the Word document for detailed directions and pedagogical decisions in this section]

Post-Do Now, this lesson starts with a group reading of the information at the top of the first page of the Altitude Diagrams resource. The work space section is designed for students to attempt to calculate the degrees/hour that the Sun moves in the sky. Oftentimes, they need some help via a few clues, and with some careful questioning, they usually are able to understand that the: (a) Earth rotates once in 24 hours and that (b) there are 360 degrees in one rotation. If they have these two pieces of information, they can calculate the rate by dividing 360 degrees into 24 hours, getting an answer of 15 degrees/hour. This is why the Sun appears to move approximately 15 degrees per hour in the sky. 

They then fill in the notes on the bottom of the first page of the resource, and then explore the image that's also on the bottom of the first page. Given that that occurs in New York state on the Spring Equinox, they can see that the Sun is in the sky for about 12 hours, rises due East and sets due West, and reaches an altitude of 48 degrees at its highest point (solar noon) on that date in the southern sky. 

After that, their job is to collectively read the information about the path of the Sun in New York State during alternate seasons. They will see that the Sun gradually gets higher in the sky as the year moves toward the Summer Solstice, where it reaches its highest point in New York state. Then, for the next six months, it will get lower and lower in the sky, until it reaches its lowest point on the Winter solstice. The Spring and Fall Equinoxes respectively serve as "midpoints" between those values, and are separated via degrees of 23.5 degrees (which matches the tilt of the Earth). 

Having collected that information and answered the associated questions on the remaining pages of the Altitude Diagrams resource, we will quickly go over the correct answers as a class before students get a chance to practice making their own altitude diagrams later in the lesson. 

Altitude Diagrams II

25 minutes

Given that this lesson is skill-based, there are no traditional Regents-based practice questions like in many of my more traditionally built lessons. 

However, the Altitude Diagrams II section still provides a challenge for students as they attempt to re-create altitude diagrams on key dates in New York State. The first one they do, which is the path of the Sun on the Equinox (the fall and spring equinoxes have the same solar path), is one I usually more directly model for them. I always start off the altitude diagrams by doing the following: 

  1. Label the top most portion of the altitude diagram as the zenith.
  2. Put the cardinal directions (N,S,E,W) on the center (on either side of the "plus" sign at the bottom center of the altitude diagram

Then, depending on the date (and latitude), I reconstruct the path of the Sun by drawing a line that represents its path during the daylight hours on that day. Where the Sun reaches its highest point on that day, I draw a small circle to represent the Sun, and then write out the angular altitude of the Sun on that day (in this case on the Equinox, it would be 48 degrees). After that, I answer the associated questions below. Here's a video I made to help explain this process below:

After that model, students get the opportunity to practice with the Summer and Winter solstice (I would leave it up to you as to how to determine if students should work independently or in pairs/groups for this. If you think you've accumulated enough data that your kiddos have a rote understanding, definitely have them give it a shot individually (they can always check their notes). If you think they might need an extra scaffold or the ability to check with a partner, you might want to open it up to group work here). If students feel particularly ready, there are two additional and final altitude diagrams for them to practice with which are not based in New York state. The first one asks students to recreate the path of the Sun at the Equator on the Spring Equinox, while the second asks them to draw the path of the Sun at the North Pole on the Summer solstice. Both are a bit tricky! 

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 THE LESSON (in this case, altitude diagrams, 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.