Transcript Star Life Cycle PowerPoint

Monday April 25
Tuesday April 26
Unit Question
What do we know about the universe? How do we know it?
Guiding Question / How do astronomers study the lifecycles of stars?
Learning Target
Warm-up
Will the sun always be there? Why? What
might happen to it?
Agenda
1. H-R Diagram and the Lifecycle of Stars
Quiz Friday
Homework
Stellar Diversity
Do all the stars look the same in this
picture?
Arrange from oldest to youngest
Questions About the Snapshots
• What is the correct order chronologically by
age?
DCHFAEGB
Questions About the Snapshots
• Was this task difficult? Why or why not?
If you were an alien…
• What are some properties and characteristics
that we could use describe people?
• What could you see or measure about
humans to compare them?
• Do some of these characteristics change over
time?
Could you do this for stars?
• Can you use the same properties?
• Would it be easier or harder?
Place the images in order for a star’s
life
Questions About the Star:
• Was this task difficult? Why or why not?
Stars Live Longer!
Classifying Stars
Stars are far away and live
billions of years
Classifying People
People (usually) live less than 100
years
Ways to describe humans
Direct Relationship
• Direct relationship or
positive correlation
• When one property is
large, the other
property is large
• When one property is
small, the other
property is small
Inverse Relationship
• Inverse relationship or
negative correlation
• When one property is
large, the other
property is small
Constant Relationship
chromosomes
• When one property
changes, the other
property stays the same
No Relationship
• When two properties
are unrelated
• When one property
changes, the other
property may or may
not change
• Stars are like pictures of unrelated people
Astronomers must look at pictures of
different stars to try to understand their
life cycle
What this has to do with stars?
• Astronomers use the properties of stars to
find out if there are any relationships between
them.
• Brainstorm observable characteristics of stars
that might help us determine age
• Will relationships between these help
determine age (or point in the life cycle) of a
star?
• Will some characteristics change over time?
Variables:
– Diameter: or (Rʘ) “size” compared to the sun,
where sun = 1
– Temperature : Kelvin (K) room temperature in
kelvin is about 293⁰
– Mass : in units of our sun (sun = 1)
– Luminosity : (brightness) in units of our sun (Lʘ),
how many times brighter / dimmer is it.
– Color
Consider
this
yellow.
ignore
Numerical data
here
H-R diagram explorer
• Quickly sketch the changes to the left star as
you go through variables
• Be sure to write your numeric data!
In pairs
One side of whiteboard:
• Write a claim about the
relationship between
temperature and color.
Other side of whiteboard:
• Write a claim about the
relationship between radius
and luminosity.
Graphing other properties
From a database of 90 stars, look at the graphs comparing Diameter,
Temperature, Mass, and Luminosity.
As a pair
• Tell me the relationship
• Rank for strength
Graph
Mass v. Diameter
Temperature v.
Diameter
Luminosity v.
Diameter
Mass v. Temperature
Mass v. Luminosity
Temperature v.
Luminosity
Relationship Strength (1 most, 6 least)
As Partners
• Pick your top two strongest relationships to
write on your whiteboard
• Be ready to explain why you chose these
graphs
Mass v Diameter
Temperature v. Diameter
?
Luminosity v. Diameter
Mass v. Temperature
Mass v. Luminosity
Temperature v. Luminosity
Looking at your list
• Which characteristics show the strongest,
most consistent relationship?
• Which graph incorporates the most data?
– Can one characteristic tell you multiple things?
– Mass
– Temperature
– Diameter
– Color
– Luminosity
Temperature v. Luminosity
COLOR
DIAMETER
RONG CORRELATION
Graph it!
• Plot each star as a letter
Careful!
K
H-R Diagram
M
Add dots (general shape)
J
F
K
I
P
G
N
E
C
B
O
L
D
H
Red Dwarf
Exit Question
• Give an example of an inverse relationship in
humans.
Exit Question
• Where in the lifecycle of stars (example:
beginning, middle, end) are:
– White dwarves?
– Red and super giants?
• I want to here your thoughts on this, you
don’t know the correct answer yet