1. Stars
By: Mrs. Crisp

2. Twinkle, Twinkle, Little Star…
Hubble Heritage image of Sagittarius Star field. Note that along the horizontal axis, the image is 13.3 light-years across.
Ask audience what they notice by looking at this image. Hopefully they will notice the different colors. You can then ask them what the different colors mean [different temperatures]
Image from

3. S.P.I
– Identify methods and tools for identifying star patterns.

4. Academic Vocabulary Star
Star
An object in space that produces its own energy, including light and heat.
Nebula
A huge cloud of gas and dust in space that is the first stage of star formation.
White Dwarf
A star that can no longer turn helium into carbon; it cools and shrinks, becoming very small and dense.

5. Academic Vocabulary Supernova
Supernova
A star that has produced more energy than gravity can hold together and it explodes.
Constellation
Any of the patterns formed by groups of stars in the night sky.
Star Chart
A map of the night sky used to locate stars and constellations.

6. All stars form out of a nebula.
What are stars?
Star
An object in space that produces its own energy, including light and heat.
Stars go through stages or cycles, different kinds of stars have different stages.
All stars form out of a nebula.
Survival in any ecosystem is a constant struggle. Organisms with successful adaptations survive more frequently that other organisms. The individuals that survive pass on their characteristics to their young.
Nebula
A huge cloud of gas and dust in space that is the first stage of star formation.

7. As the atoms move closer, they collide with each other.
What are stars?
Stage 1
Gravity pulls the mass of the nebula (most of which are hydrogen atoms) closer together.
As the atoms move closer, they collide with each other.
The collision produces heat and the temperature in the cloud begins to rise.
When the temperature reaches millions of degrees Celsius, hydrogen atoms combine to make helium atoms.
This gives off large amounts of heat and light creating a Protostar, or beginning star.

8. Now, the helium atoms combine to form carbon atoms.
What are stars?
Stage 2
For a few billion years, hydrogen (the fuel to produces energy in the sun) combines to form helium and the star increases temperature.
Eventually, the heat forces the hydrogen on the edge of the star to expand into space.
As the expanding hydrogen moves further away from the center of the star, it cools and turns red. This is called a red giant.
Now, the helium atoms combine to form carbon atoms.

9. What are stars? Stage 3 – Medium Star
This stage depends on the mass of the star.
When all the helium is gone, the star begins to cool and shrink, this is called a white dwarf.
White dwarf stars shine very brightly.
The white dwarf stage is the end of the medium star cycle.
(The heaviest stars end their cycles differently.
White Dwarf
A star that can no longer turn helium into carbon; it cools and shrinks, becoming very small and dense.

10. What are stars? Stage 3 – Heaviest Stars See photo on pg. 174-175
After they have become red giants, the temperature of these stars reach 1,080,000,000 degrees.
At this temperature, the stars atoms combine to form iron atoms.
Eventually, the iron core produces more energy than gravity can hold and the star explodes.
The exploding star is called a supernova.
A supernova will form a new nebula.
See photo on pg

11. How are stars characterized?
Stars are characterized by their size, color, and temperature.
Size
Giant stars have a diameter between 10 – 100 times the Sun.
Red supergiants are the largest. They have diameters of 1,000 times the Sun.
White dwarfs are some of the smallest stars and can be about the size of Earth.
Neutron stars are the smallest stars.
Color – Tells you about its surface temperature.
Red/Orange: Cooler stars
Yellow: Hot
Blue: Hottest
(The sun is a medium sized yellow star with a temperature of 10,832 degrees F.)
Apparent Magnitude
How far a star is away from the earth and how
bright a star is.

13. What are Constellations?
Any of the patterns formed by groups of stars in the night sky.
Ancient Greeks and Romans gave names to many star patterns. These names were often taken from animals, heroes, etc.
Constellations are often used by travelers today as they were to ancient travelers. (For example, if you can find the Big Dipper or Little Dipper, you can follow the line their stars make to find Polaris, the North Star.

14. Modern Constellations
Astronomers have divided the sky into 88 constellations. Many of these still have the same ancient names they were given many years ago.
The stars you can see depend on your latitude on Earth.
Some stars never rise above the horizon in Greece and Italy; therefore, ancient Greeks and Romans did not have these stars.

15. What are Star Charts? Star Chart
A map of the night sky used to locate stars and constellations.
Star charts help us locate a star or constellation.
Dots on a star chart represent the stars.
See page 180 to learn how to use a star chart.

16. Why do constellations seem to move?
The patterns in the night sky always look the same but seem to change position during the night and from season to season.
As the Earth rotates, the stars appear to complete one full circle in the night sky.
Some constellations are visible all year long while others are not.