Constellations are Seasonal
Lesson 3 of 9
Objective: SWBAT describe why we see some constellations all year round while others we can only see at certain times of the year.
The Why Behind Teaching This
Unit 6 teaches students about Earth's Place in the Universe. Standard 5-ESS1-1: Support an argument that differences in the apparent brightness of the sun compared to other stars is due to their relative distance from Earth, is one standard covered. Standard 5-ESS1-2: Represent data in graphical displays to reveal patterns of daily changes in length and direction of shadows, day and night, and the seasonal appearance of some stars in the night sky, is the other standard covered.
Throughout this unit, students will learn about classifying stars, patterns of stars, and the effects of rotation and revolution. We will be creating models, graphing data, tracing our shadows, and much more.
This specific lesson covers standard 5-ESS1-2 by having students investigate how the constellations seen from Earth change as the Earth revolves around the sun. In this lesson students help build a model by creating an image of a given constellation. Each student then becomes part of the model by representing the Earth. They rotate and revolve around the room illustrating their view of the constellations in the night sky.
The goal of this lesson is for students to be able to describe how our view of the constellations in the night sky is impacted by Earth's revolution.
Students will demonstrate success on this goal by correctly describing both ways our view of constellations is impacted by the revolution on the exit card provided.
Preparing For The Lesson:
- Prepare an illustration of the Big Dipper and Little Dipper on black construction paper.
- Have construction paper signs prepared for each Zodiac sign. The name of the constellation should be on one side, along with the birthdays that fall under that sign. On the others side of the construction paper should be a picture of the constellation and information about when it can be viewed in the night sky.
- 12 sheets of large black construction paper or black bulletin board paper
- White chalk
- A large circle cut out of yellow paper, taped to a chair, and placed in the center of the room to model the sun.
- A copy of the Constellation Model Investigation Sheet for each student
- An index card for each student
I have two pieces of black construction paper hanging up on the board. I used white chalk to create an image of the Little Dipper on one and an image of the Big Dipper on the other. I chose these two because they are well known and students will recognize them. I also chose them because they are circumpolar constellations which we will discuss later.
I ask students to discuss the two pictures with their group and record as much information as possible about them on a whiteboard. For the next 3-4 minutes groups discuss the pictures and record information as I circulate to listen to conversations.
By starting the lesson with this activity I am able to determine how much background knowledge students have about constellations. I am also able to make connections to previously taught lessons such as Our Solar System and Classifying Stars.
The information that groups record about the two pictures is that they are constellations, one is the Big Dipper and the other is the Little Dipper, they are made up of stars, Polaris is the star at the tip of the Little Dipper (they know this from the classifying stars lesson), and all the stars in them are in the Milky Way Galaxy.
Seasonal Constellations Versus Circumpolar Constellations
I have the front board separated into two sections. One side is labeled as Seasonal Constellations and the Other Side is labeled as Circumpolar Constellations. The Big Dipper and the Little Dipper are listed under the Circumpolar Constellations. There are pieces of construction paper taped to the other side of the board. These pieces of construction paper are labeled with the constellations for each Zodiac sign: Capricornus, Aquarius, Pisces, Aries, Taurus, Gemini, Cancer, Leo, Virgo, Leo, Scorpius, and Sagittarius. I chose to use these constellations because students are familiar with them and I am using it as a way to group students. Under the name of each constellation I have written the dates of the birthdays that fall under each sign. This will help students who are not familiar with their sign choose the correct one. On the back of the construction paper is a picture of the constellation. A couple of examples of these papers are below.
I explain to students that constellations are classified into two categories, seasonal and circumpolar. I ask them what they think the seasonal constellations are. They tell me that they are only visible during certain seasons. I ask them what they think circumpolar constellations are. I tell them to think about the prefix circum first. They tell me that circum means to circle so it must mean to circle the pole. I tell them that both are correct, seasonal constellations are only visible certain times of the year and circumpolar are visible all year because they are in the night sky around the poles. There are different circumpolar constellations for the northern hemisphere and southern hemisphere. The Big Dipper and Little Dipper are two northern hemisphere circumpolar constellations. They can be seen from anywhere in the northern hemisphere all year.
Creating Images of Constellations
I take each construction paper sign down from the board and ask students to raise their hand if their birthday falls in the date range listed. I have those students form a group and hand them the construction paper. Not all signs are passed out because there are certain ones that no birthdays fall in. I just leave those out. If there are any large groups (more than 3 students) I would split it up and assign 2 of the students to one of the signs not being used. This did not happen for my class though.
On the construction paper sign, there is a picture of the constellation and information about what season/month it can be seen in the night sky. I provide each group with a large piece of black construction paper and white chalk. I tell them to recreate the image, larger, on the black construction paper. You can see in the video of students creating the constellations that some chose to use dots to represent the stars, and others actually drew little stars. I did not give them specific directions on what I was looking for so either was fine. As students create the posters, I hang my drawings of the Big Dipper and Little Dipper on the ceiling.
Becoming Part of a Life Size Model
I have a large circle of yellow paper taped to a chair in the middle of the class. This represents the sun in our model. I have signs hanging up around the room labeled with each month of the year. As groups finish their constellation image I hang them up on desks that are positioned in a cirlce around the "sun" . I found this information on the American Association of Amateur Astronomers website.
I provide each student with a copy of the Constellation Model Investigation Sheet. I demonstrate how each student will become the Earth in the model. I begin at the sign that says January. I am facing the sun and ask the students if I am modeling day or night. They tell me day. I spin around so that my back is to the sun and ask if I am not modeling day or night. They tell me night. I point to the picture of the Gemini Constellation and tell them that this is one of the many constellations I would see at night. I draw a picture on my investigation sheet of what I see. I then look up and draw an image of what the Big Dipper and Little Dipper look like to me in January. I then rotate and take a step counter clockwise, this takes me to daytime in February. I spin around to my night view and explain that I would then draw an image of the Cancer constellation.
I model this before letting students begin the investigation so that I can point out what day and night look like. I also model it so that I am sure students know they should be illustrating only the picture in front of the them, and the image of both the Big Dipper and Little Dipper each month. Another benefit of modeling for them is to review rotation and revolution, and to make it clear that the Earth revolves counter clockwise.
I assign two students to each month and allow them to begin. I give them about 1 minute at each position before telling them to rotate. You can see in the video of students completing the constellation investigation that students stood in front of the posters and drew the images, then looked up at the ceiling to diagram the circumpolar constellations.
The purpose of including the Big Dipper and Little Dipper on the ceiling is so that students can see that although they are visible from all positions, they do appear to change. Circumpolar constellations appear to rotate throughout the year which students can visualize in their completed drawings on the investigation sheet.
Sharing Information From the Investigation
I ask students if the Big Dipper and Little Dipper always looked the same. They all say no, that it looks like it changes position or spins around. I ask them what causes this and they tell me the revolution of the Earth around the sun. I point out that we see different constellations at different times of the year because of the Earth's position in its orbit. This also causes the circumpolar constellations, which we see all year, to appear in different positions. I show a couple of the investigation sheets that are well illustrated on the overhead. This helps students visualize what I am discussing, especially for those that may not have illustrated them correctly.
The exit ticket today is very simple. I provide each student with an index card. I ask students to answer the following question on the index card:
How does the revolution of the Earth affect our view of the night sky?
Once I collect all cards, I divide them into three groups. One group consists of cards from students who listed both the fact that we see different constellations at different points in the year, and that the circumpolar constellations appear to rotate. Another group is made up of cards that have only one of these facts listed. Both of these groups are considered as passing because I did not tell them they had to list 2 ways the revolution affects constellations. I had 3 out of 20 list both change to circumpolar and seasonal constellations. 15 out of 20 listed only one of the impacts on constellations, the majority being seasonal constellations are viewed at certain times of year.
The last group consists of cards that do not have either of the facts listed. There were only two cards in this pile and neither of these students even attempted an answer. One left it blank and the other put a question mark. For these two students, I will reteach the differences between the two types of constellations with images from the internet.