1. The Life of a Star Cathcart science

2. “Which motion of earth causes which apparent motion of stars?” Rotation= the earth is spinning Revolution=the earth orbits the sun Stars appear to circle Polaris during the night. Different constellations are visible different months of the year.

3. A star begins…. …as a ball of gas and dust. Gravity pulls the gas and dust together into a sphere. The sphere becomes dense and hot. Nuclear fusion changes hydrogen to helium.

4. Main-sequence stars…. ….are in the second and longest stage. As long as they have hydrogen atoms to fuse into helium atoms they just keep on releasing lots of energy.

5. Red giants…. ….are what stars can become after the main-sequence stage. This is a star that expands and cools because it has used up all of its hydrogen. The center of the star shrinks, but the atmosphere gets very large. The star may become a supergiant (100 times bigger than the sun).

6. White dwarfs…. …..are stars in their final stages. This is a small hot star that is the leftover center of a star. A white dwarf can no longer generate energy, but it can keep shining for billions of years

7. Really massive stars…. …might not make it to the white dwarf stage. Massive stars might explode in a bright flash called a supernova. A supernova can be brighter than a whole galaxy.

8. A neutron star… …forms from the center of a massive star that has exploded into a supernova. A neutron star has collapsed under gravity to the point that all of its particles have become neutrons.

9. A pulsar…. ….is a neutron star that is spinning.

10. If….. …..the center of the collapsed star is massive enough ….and it collapses further because of the strength of its own gravity ….it could become a black hole.

11. A black hole….. ….is a place in space where the gravity is so strong nothing can escape not even light.

12. You have a choice… You may write a story about the life of a star. Or You may create a comic strip about the life of a star. Either way, you will be graded as follows:

13. Your star must… Begin as a ball of gas and dust. Go from there to main- sequence, red-giant or supergiant, then to white dwarf. Or be a massive star that goes from main-sequence to supernova to neutron star (perhaps pulsar) and perhaps becomes a black hole.

14. For a perfect grade.. The stages need to be named. The stages need to be in order. The story or comic strip needs to show an understanding of each stage. EXTRA POINTS FOR ENTERTAINING THE TEACHER!