Stellar Evolution Lab Spying into the lives of the stars
Developed by: Betsy Mills, UCLA NSF GK-12 Fellow Title of Lesson: Stellar Evolution Lab! Grade Level: 8th Subject(s): Astronomy: Stars, the Sun, and Stellar life cycles Summary: Students will rotate through 4 stations Time Required: 15-20 minutes for each lab station; 60-90 minutes total. Group Size: Divide class into 4 groups to rotate through each station. Cost to implement: ~$10 for colored beads or sprinkles Learning Goals: Red stars are colder than blue stars We are made out of elements that came from stars, and the deaths of stars The sun is just one of many di"erent types of stars The sun will never become a supernova Level of Inquiry: This lesson incorporates inquiry by having students observe, predict, and draw conclusions from di"erent sources of data. Safety Issues: DO NOT do Part One of this activity without a professional solar filter on your telescope, which you are trained to use. LOOKING AT THE SUN DIRECTLY WITH A TELESCOPE CAN CAUSE BLINDESS AND SEVERE EYE INJURY. If you do not have access to a telescope, Part one can be done by having students look at a current picture of the sun, such as are available online. Materials List: small tupperware containers sprinkles or beads Large sheet of paper Colored poster board or construction paper Tape Solar telescope
Introduction / Motivation: To introduce the lab, ask students what they know about stars. Explaint that we know that, like humans, stars are born, grow up, and die. It s just that stars take longer to do these things: millions and billions of years. You can t really just take a single star and follow it from birth to death, so today, we will use some of the tools that astronomers use to study stars and find out about how they live and die. Procedure: Have students break into four groups. Rotate students through the four stations, having them fill out an attached worksheet for each station. Lesson Closure: After students have completed all of the stations, have them share their Haikus with the class. Use this as an entry into a discussion of stellar evolution using the stars from the H-R diagram. Ask them, which of these stars will a star like the sun turn into? (a red giant, a white dwarf) What happens in between those two stages (a planetary nebula) Will the sun ever become a supernova? (no) Which of these objects will? (A high mass star, which turns into a red supergiant before exploding) References: Information on the Hertzspring-Russell diagram: http://www.daviddarling.info/encyclopedia/h/hrdiag.html List CA Science Standards addressed: 4b: Students know that the sun is one of many stars in the Milky Way galaxy and that stars may di"er in size, temperature, and color. Attachments: Worksheets for each station are attached, as well as descriptions of the setup required for each station.
Station Setups: Station 1: Telescope with Solar Filter. DO NOT use a telescope without a professional grade solar filter If you do not have access to a telescope, use a current picture of the sun from one of the following websites:! http://www.spaceweather.com! http://www.spacew.com/sunnow/! http://sohowww.nascom.nasa.gov/
Station 2: Small containers with the following mixes of beads: Container 1: Sun (75% Hydrogen, 25% Helium) Container 2: Planetary Nebula* (Approximately 50% Nitrogen, 30% Carbon, 10% Oxygen) Container 3: Supernova* (Approximately 70% Oxygen, 20% Carbon, 10% Calcium) Container 4: Human (65% Oxygen, 20% Carbon, 10% Hydrogen, 3% Nitrogen, 1% Calcium) *Important note: The given compositions of Planetary Nebulae and Supernovae are NOT perfectly representative of their actual compositions. Planetary Nebulae and Supernovae are actually still mainly dominated by Helium and Hydrogen. Omitting the Hydrogen and Helium in these two objects makes it easier to see that these objects are important sources of other elements: The small amounts of Carbon and Nitrogen Planetary nebulae release are the main sources of these two elements in the universe. Similarly, Supernovae are the main sources of Oxygen, Calcium (and some Carbon) in the universe. Give students a key to explain what each color is (For example: Blue = Oxygen, Green = Carbon, Yellow = Hydrogen, Orange = Nitrogen, Red = Helium, Purple = Calcium) Station 3: No setup needed, beyond giving students access to textbooks or other sources if they desire them.
Station 4: For this station, you will need the following drawn on a large sheet of paper: 1,000,000x as bright as the Sun 100,000x as bright as the Sun 10,000x as bright as the Sun 1000x as bright as the Sun 100x as bright as the Sun 10x as bright as the Sun As bright as the Sun 1/10x as bright as the Sun 1/100x as bright as the Sun 1/1000x as bright as the Sun 30,000 10,000 9000 8000 7000 6000 5000 4000 3000 Degrees Celsius This type of chart is called a Herztsprung-Russell or H-R Diagram It lets astronomers map out how stars live and die, and compare their properties. For this activity, it will show students how the colors and sizes of stars relate to their temperatures and brightnesses.
You also need the following six colored shapes cut out, with relative sizes preserved (Try to use sizes ranging from a large paper plate to a quarter). For each circle, write or otherwise attach the associated brightness and temperature of the star Red Supergiant Brightness = 100,000 x as bright as the sun Temperature = 3000 o C Red Giant Brightness = 10,000 x as bright as the sun Temperature = 4000 o C High-mass Star Brightness = 100,000 x as bright as the sun Temperature = 30,000 o C Sun Temperature = 6000 o C Red Dwarf Brightness = 1/100 x as bright as the sun Temperature = 3000 o C White Dwarf Brightness = 1/1000 x as bright as the sun Temperature = 10,000 o C
NAME: 1. Our nearest star A lot of what we know about stars come from studying the closest star, the sun! Most stars are located light years away, but our nearest stellar neighbor is just eight light MINUTES away. Did you know that means that the Sun could explode, and we wouldn!t know about it until eight minutes later?? (Don!t worry, the sun can!t actually explode) Draw what you see on the sun looking through the telescope. Try to pick out just a couple special things and draw their position as perfectly as you can! Imagine that you were going to look at the sun again tomorrow, and wanted to be able to compare it to what you just saw today. How many earths do you think fit inside the sun? Write down one thing you learned about the sun that you did not know:
NAME: 2. We are all Star Stuff Have you ever thought about where all of the different atoms in your body came from? Just like the fact that right now you could be breathing in the same air molecules that Einstein, Michaelangelo, Caesar, Galileo or Shakespeare once breathed in, the atoms that make up your body weren t always part of the earth! I breathed that air first. At this lab station, there are four samples of the atoms in four types of objects. A: The sun (a normal young star) B: A planetary nebula (the leftovers after the death of a star like the sun) C: A human ( inhabitant of a planet around a normal young star ) D: A supernova (the leftovers after the death of a star BIGGER than the sun) There is also a key that tells you which color represents which atomic element. Be very careful! Two of the colors look VERY similar. What two elements are most stars made out of? Where do you think most of the carbon in humans comes from? Where do you think most of the oxygen in humans comes from? Where do you think most of the metals in humans come from? How can a star like the sun change from step A to step B, totally changing what it is made out of? Write down two questions you have about how stars live and die:
NAME: 3... it was written in the Stars A Haiku is a traditional type of Japanese poem. You don t need to use capitalization or punctuation, and it doesn t even have to rhyme! Each poem is only three lines long, with the following format: For example, five syllables first seven syllables after five syllables last i like science now (because we made things explode) let s do it again Your job: write a haiku about one stage of stellar evolution: red giant, supergiant, white dwarf, supernova, planetary nebula, or black hole. Try to tell as much information as you can (hint: look in the book!) about this stage of stellar evolution in the three lines you have. Think of it like tweeting or texting. Trim out all of the unecessary stuff-- dear mom, hi, how are you, sincerely, please, thanks and leave in the most important things -- pick me up from movie now! (Hey, that was seven syllables right there!) Topic: 2 important things about your topic: Practice space: Final Haiku:
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