Our Star?
Several students were having an argument about our sun.
Tim: “The sun is one of several stars in our solar system.”
Johnna: “The sun is a major star. All the other stars are much smaller.”
Damonte: “No, the sun is just an average star made up of hot glowing gas.”
Kim: “The sun is a ball of hot, glowing gas, but it is too close to us to be a star.”
Anne: “The sun is a sun, not a star. Suns are different from stars.”
Lee: “The sun was once a planet but now is a burning ball.”
Bill Nye the Science Guy: The Sun
Sci Show Kids: What are Stars?
Sirius and Rigel
Tim: “The sun is one of several stars in our solar system.”
Johnna: “The sun is a major star. All the other stars are much smaller.”
Damonte: “No, the sun is just an average star made up of hot glowing gas.”
Kim: “The sun is a ball of hot, glowing gas, but it is too close to us to be a star.”
Anne: “The sun is a sun, not a star. Suns are different from stars.”
Lee: “The sun was once a planet but now is a burning ball.”
Bill Nye the Science Guy: The Sun
Sci Show Kids: What are Stars?
Sirius and Rigel
Our Star?
5-ESS1-1. Support an argument that differences in the apparent brightness of the sun compared to other stars is due to their relative distances from Earth.
The sun is a star that appears larger and brighter than other stars because it is closer. Stars range greatly in their distance from Earth.
- The sun is a star.
- The sun looks bigger than other stars because it is much closer.
- Other stars appear small because they are very far away from Earth.
- Stars vary in size.
- Many stars are larger than the sun; the sun is just closer.
- Some stars are very far away and some are closer to Earth.
Adapted in part from “Is the Sun a Star?” from the National Science Teachers Association, retrieved from http://www.livebinders.com/play/play?id=1268678#anchor
Before: Acquire two identical flashlights. Play around with flashlight setup (as in Expand) to ensure that you are showing what is needed..
Seek: What is the sun? Display the following statements from students and ask students with which one they agree:
Several students were having an argument about our sun.
Tim: “The sun is one of several stars in our solar system.”
Johnna: “The sun is a major star. All the other stars are much smaller.”
Damonte: “No, the sun is just an average star made up of hot glowing gas.”
Kim: “The sun is a ball of hot, glowing gas, but it is too close to us to be a star.”
Anne: “The sun is a sun, not a star. Suns are different from stars.”
Lee: “The sun was once a planet but now is a burning ball.”
Try: Show the Bill Nye the Science Guy on the sun: https://vimeo.com/107050146 from the beginning through 2:53.
Show What are Stars? from Sci Show Kids: https://www.youtube.com/watch?v=ZrS3Ye8p61Y Have students take notes.
Key notes ideas:
- The sun is a star.
- The sun is really big, compared to Earth.
- The sun looks small because it is very far away from Earth.
- The sun and all stars are hot balls of glowing gas; they give off light and heat.
- The sun isn’t really a big star; many are bigger.
Revisit the initial statements. Which one now seems correct? Why? Explain how each statement except Damonte’s is incorrect. If time allows, have students explain why each is wrong.
Make Connections: Support a claim: The sun seems brighter than other stars only because it is much closer. What is the sun? What are stars? Why does the sun seem brighter than the stars? Why do stars seem so small? Encourage students to use their notes.
Student page
Extension: Adapted from: MySci Unit: Our Place in the Universe: http://schoolpartnership.wustl.edu/wp-content/uploads/2014/08/unit23_universe_080614_v5.pdf
Before: You will need a small, dimmer flashlight and a larger, brighter one. Try the activity ahead of time so you know the approximate locations for the flashlights. You will need the room to be dark for this demonstration.
Seek: Show an image of the night sky (such as the one found at http://upload.wikimedia.org/wikipedia/commons/5/51/Night-sky-milky-way-galaxy-astrophotography_-_West_Virginia_-_ForestWander.jpg) Our sun is our star; it’s the star closest to us. It looks really bright to us, much brighter than the other stars. Can the brightness of a star tell us about its distance from the Earth? Why or why not?
Try: Have the students walk to the back of the classroom. Place the small flashlight near the students and the larger one farther away so students can see the light from each. Turn on both flashlights and observe and compare their brightness. Move the flashlights’ relative distances from the students until they appear to be the same brightness level.
Expand: What makes a star seem bright to us? If you didn’t know that the flashlights gave off a different amount of light, could you tell that by observing them? Our star, the sun, seems really bright because it is very close to us. But there are many stars that are much bigger.
You can think of these flashlights as the stars Sirius and Rigel. Sirius looks twice as bright as Rigel (see image: http://www.eriktonnesen.com/EarthScience/_Media/sirius_rigel_nasa_med.jpeg) but Rigel is about 100 times further away. Both of them are much bigger than our sun.
Watch video comparing relative sizes of planets and stars: https://www.youtube.com/watch?v=HEheh1BH34Q
Make Connections: Why does our sun seem brighter than the other stars? Can you tell the size of a star by how bright it is?
Extend: Cosmos: A Space Time Odyssey
Bill Nye on Outer Space: https://www.youtube.com/watch?v=WHyl0TevzSs