Motion of Stars in the Sky

By Rich Hedman Motion of Stars in the Sky January 29, 2013 3rd/4th/5th grade science strand Focus: Astronomy Standards Grade 3 Std 4; Grade 5 Std 5

Goals for Workshop • Two main goals: • To develop in each of you an understanding of the science content. • To encourage each of you to use a student-centered and data-centered instructional approach.

Instead of the more traditional teacher-centered approach. Not in this workshop today

However, the instructional approach is highly teacher-guided.

So I will avoid “telling” you about stars tonight. • Instead I will present you with data on stars from which you can construct your own understanding. • When I ask you questions, I am seeking your ideas and your evidence, not a “right answer”. (although my goal is for you to eventually get there) • I will try to not answer your questions directly, but will seek to have you figure it out yourself. • I encourage you to take the same approach if you teach these lessons to your students. • This student- and data-centered instructional approach is aligned with how people learn science and how scientists engage in their work.

Rules of Engagement • Be considerate and respectful in language and tone. • Make sure everyone has a chance to express their ideas. • Try to not steal anyone’s “Aha!” moment by “telling” them your “answers”—instead ask questions that will guide your group to these ideas. (ask, don’t tell!)

The Science • Part One: Evidence of Motion • Part Two: Day & Night • Part Three: Star Data Using Stellarium Software • Part Four: Stars During One Night • Part Five: Stars Over Many Nights, Weeks, Months • Part Six: Make and Understand a Star Finder

Evidence of Motion • How do you know something is moving? • Pair-share. • To know if something is moving, we need: • An object of interest • A reference point • A period of time • And: we should understand our point of view • 1st person (personal view) versus 3rd person (objective view)

Sun & Motion Question • Question: Based on our ideas of motion, in the 1st person perspective, if you are outside for an hour on a clear day, is the sun moving? • Think quietly about that for a moment. • Share your thoughts. • We will come back to this later…

Observations: Day, Night, & the Sun • Question: What are some observations that you have about day, night, and the sun? • Work with your group to list some of your observations on the whiteboard. • Be prepared to share an observation or two.

Model: Day & Night • A model is a coherent set of ideas. • What set of ideas could explain the patterns in day & night you described? • With your group, write down a list of statements about what causes day and night, AND also be able to explain your ideas with the 3-D objects: • Earth beach ball, light representing the sun. • Be prepared to share your model. • I will capture the model on chart paper.

Sun & Motion Question • Let’s revisit the question: Based on our ideas of motion, in the 1st person perspective, if you are outside on a clear day, is the sun moving? • 1st person is the earth-bound view. • If your reference point is your local horizon, then the sun is moving with respect to your horizon. • If your reference point is the sun, then the horizon is moving with respect to the sun. • We must have a 3rd person perspective to figure out which statement is more correct. Which is it?

Star Motion in Sky • Now that we understand how the sun “moves through the sky”, we need to look at how the stars move. • Thought question: If you were to go outside on a clear night, and watch the stars all night, what would you see? Would the stars move? If so, how, exactly? • Don’t forget our conventions about describing motion. • Share some ideas.

Star Motion Data • We need data to answer the question! • We will get this data using the free astronomy program Stellarium. • Stellarium can be downloaded from: http://www.stellarium.org/ Instructions: • Form into pairs (computer-savvy + computer-not) • Get a laptop, power it up. • Open up Stellarium:

Stellarium Controls—mouse over left side of screen, and bottom of screen. Set Location here.

Type Sacramento into the search box. • Then click on Sacramento, United States. • Note: Make sure the red dot is in the right place. • Close Location Window when finished

One way to set Time and Date is here.

You can click on the up and down arrows to adjust the date and time (military time). You can drag the box around so it doesn’t block your view, or just close it.

Click each bottom icon ON and OFF to see what it does. The bottom right controls can speed up or reverse time.

Two final things: • Hold down left mouse button, and drag mouse across screen to change your view. • Use your mouse scroll button to zoom in or out, or use / to zoom in, and \ to zoom out.

Observations: Stars During 1 Night • Question: What patterns do you notice in the motion of stars over a night from Sacramento? • Use Stellarium to take your observations. • Start by looking south. Then look east and west. Then look north. • Write the patterns you notice on your whiteboards. • Be prepared to share your observations.

Animations of Stars During 1 Night • If there is time, watch animations of the stars during 1 night in Sacramento, looking in each direction. • QUESTION: How can these patterns be explained?

Model: Stars During 1 Night • A model is a coherent set of ideas. • What set of ideas could explain the patterns you noticed in the motion of stars over a night from Sacramento? • With your group, write down a list of statements about what causes the patterns in the motion of stars, AND also be able to explain your ideas with the 3-D objects: • Earth beach ball, light representing the sun, constellation sheets. • Be prepared to share your model. • I will capture the model on chart paper.

If Needed: Quick Activity on Star “Motion” • Spin in your chair. Tell me what you see. • Make sure to include the direction of motion. • Does this remind of you of any observations? • Now look up while you spin. Tell me what you see. • Does this remind of you of any observations?

Can you explain this picture with your model?

Observations: Stars Over Days, Weeks, and Months • Question: What patterns do you notice in the motion of stars in the sky at the same time of night in Sacramento, over days, weeks, and months? • Use Stellarium to take your observations. • Start by looking south. Then look east and west. Then look north. • Write the patterns you notice on your whiteboards. • Be prepared to share your observations.

Model: Stars Over Days, Weeks, and Months • What set of ideas could explain the patterns you noticed in the motion of stars at the same time of night in Sacramento over days, weeks, and months? • With your group, write down a list of statements about what causes the patterns in the motion of stars, AND also be able to explain your ideas with the 3-D objects: • Earth beach ball, light representing the sun, constellation sheets. • Be prepared to share your model. • I will capture the model on chart paper.

Models of Star Motion in Sky • Our models can be used to explain: • Day and night. • The sun’s apparent motion through the sky. • The apparent motion of the stars through the sky: • Over one night • Over many nights, weeks, and months • Now let’s see if our models can help us understand a common tool, a star finder.

Task: Make a Star Finder • Follow the instructions. I have a sample for reference. • You need the 2 sheets (below), scissors, and tape.

Using the Star Finder • With your group, figure out how to use the star finder to predict the position of the stars you would see in the sky at 9pm tonight. • Make sure everyone in your group knows how to use the star finder. • Once you are ready, I will test you. I will ask you the name of a constellation from Stellarium.

Understanding the Star Finder With your group, answer these questions: • Why are the East and West compass directions reversed? • Why do we need an oval cut-out, what does this represent? • Take the “wheel” of stars out and look at it. What does this represent? • Explain why there are marks indicating the time of day—what does that represent physically? • Explain why there are marks indicating the month and date—what does that represent physically? • Could you use this star finder to predict the patterns of stars you would see in the sky if you lived in Brazil? Explain. • Could you use this star finder to predict the patterns of stars you would see in the sky if you lived on the earth’s North Pole? Explain.

California Science Content Standards Addressed: Grade 3 Standards: 4. Objects in the sky move in regular and predictable patterns. As a basis for understanding this concept: • Students know the patterns of stars stay the same, although they appear to move across the sky nightly, and different stars can be seen in different seasons. • Students know the way in which the Moon’s appearance changes during the four-week lunar cycle. • Students know telescopes magnify the appearance of some distant objects in the sky, including the Moon and the planets. The number of stars that can be seen through telescopes is dramatically greater than the number that can be seen by the unaided eye. • Students know that Earth is one of several planets that orbit the Sun and that the Moon orbits Earth. • Students know the position of the Sun in the sky changes during the course of the day and from season to season. Grade 5 Standards: 5. The solar system consists of planets and other bodies that orbit the Sun in predictable paths. As a basis for understanding this concept: • Students know the Sun, an average star, is the central and largest body in the solar system and is composed primarily of hydrogen and helium. • Students know the solar system includes the planet Earth, the Moon, the Sun, eight other planets and their satellites, and smaller objects, such as asteroids and comets. • Students know the path of a planet around the Sun is due to the gravitational attraction between the Sun and the planet.

Thank You • Contact information: • Rich Hedman hedmanrd@csus.edu • All files (instructor notes, handouts, PowerPoints, videos) used in this presentation may be downloaded from: http://saspcsus.pbworks.com

Motion of Stars in the Sky