Summer Research Program for Science Teachers
STAR LIGHT, STAR BRIGHT : EXPLORING HOW STARS ARE CLASSIFIED
Joanne DeMizio, Sacred Heart School, Staten Island
- Students will work in small groups to organize stars into different categories based on observations of properties for a collection of stars
(Teaching Standard E).
- To have students gain an insight into how advances in the understanding of various phenomena and/or objects can follow directly from improved systems of classification.
- To understand that much of what we know about stars came from scientists who studied patterns which appear when star surface temperature and luminosity are plotted.
- To understand and use the Hertzprung-Russell (H-Z) diagram
Assorted sized and colored stars containing star names, temperature, relative luminosity (Attachment 1), glue, markers, H-Z diagrams for each child
Time: About two (2) 50 minute periods Special Arrangements : Groups of 3 to 4 students
Grade Level : 5th - 8th Grade
Prior Knowledge and Understandings Required:
1. Our sun is an average star among numerous other stars in the universe. It has a life cycle and one day it will stop shining.
2. The sun shines because of a process known as nuclear fusion during which tremendous amounts of energy are emitted as light and heat. Hydrogen is used in this process
3. Our sun has a limited supply of hydrogen (the fuel) to fuse into helium and the sun's mass determines how much fuel it has in it.
4. The sun's luminosity is a measure of the total amount of power it gives off into space during nuclear fusion.
Motivation: Give groups of children a complete deck of playing cards and ask them to tell you what they know about them. (2 colors, 4 suits, range of 2-10 in the number cards; picture cards and aces) .
Discuss briefly how easy it was to describe the cards in this way using these categories and how someone who never saw a deck of cards would know a tremendous amount of information about them. Lead into a discussion of how organizing information can help us learn more about objects and their similarities and differences. Elicit examples of this the children may already be familiar with in science (Animal kingdoms, elements, types of clouds, etc.).
Invite them to be scientists who study the stars and to discover patterns and classes .
Activity : 1) Divide class into groups and hand out sets of star data (Approximately 25 stars)
2) Ensure that students understand what type of information is known about each star by examining the sun as a class. Make sure children notice each star has a name, a color, a temperature and a luminosity value. Make sure they understand the luminosity is compared to the sun's luminosity such that a value greater than 1 means it is that many times the sun's luminosity. A value less than one means it is that fraction of the sun's value.
3) Allow 20 minutes for the groups to become familiar with the stars and encourage the groups to write down what they are noticing. Encourage the children to spread the stars out on their tables to examine them more easily. (Teaching Standard E)
4) Circulate the room and ask questions to facilitate observations beyond just color and sizes (Teaching Standard B) (white, yellow, orange, red, and blue) / (small, medium and large)
Color and Size (smaller stars are white, middle stars are mostly yellow and white but seem to be in all the colors; large stars are orange, red and blue)
Size and Luminosity (smaller stars are less luminous than the sun; larger stars are more luminous than sun)
Color and Temperature (blue stars are the hottest; red stars are the coolest)
5) Each group should report some of their findings as the teacher starts to record these on the board. (5-8; Content Standard A)
6) When all groups have reported on their findings ask the class to summarize conclusions from these observations.
Ask: What can we say about small stars? (less luminous, mostly white and yellow)
What can we say about medium stars? (all temperatures and extremes in luminosity;
most of the stars are medium sized)
What can we say about large stars? (coolest; most luminous, mostly orange and red)
Why do you think the bigger stars are more luminous? (they have more mass)
7) Instruct each group to arrange the stars on the poster boards which communicates the most information. Challenge them to consider a way that presents all the information discussed. Allow about 20 - 30 minutes.
Homework: Each child should write a brief paragraph explaining what they did today and what they observed about the star data.
1. Each group will present and explain their poster arrangement to the class.
2. Hand out H-R diagrams to each student. Have them examine the title and the axis labels.
Identify the location of our sun on it.
3. Explain importance and purpose of this diagram
4. Ask probing questions as students use it to answer:
Where are the largest stars?
Where are the coolest and dimmest stars?
Where are the coolest and brightest stars?
Where are the hottest and dimmest stars?
Where are the hottest and brightest stars?
What do you think... colors tell us about temperatures of stars?
... temperature tells us about luminosity?
... size tells us about luminosity?
5. Close by reinforcing how much they learned about stars yesterday and behaved much like scientists in the 1800s who used similar information to create a diagram that has helped astronomers learn much about the properties of stars. (5-8; Content Standard G)
Assessment: A H-Z diagram will appear on a written exam after the unit on Astronomy is completed.
Extension: Have students research the scientists who were involved in the early data collection and analysis of stars in the 1800s. The research can take the form of a report, poster, or interview article