Chapter 1
Earth Science
Course: Elementary Education Multiple Subjects 5001
Subject: Elementary Education Science Subtest 5005
Chapter: Earth Science
1. Stars and Galaxies
Stars
- Stars are massive spheres of plasma that produce energy through nuclear fusion, where hydrogen atoms fuse into helium under extreme pressure and temperature.
- The closest star to Earth is the Sun, which supports all life by providing light and heat.
- Stars are classified by color and temperature:
Blue stars are the hottest.
White and yellow stars (like the Sun) are moderate in temperature.
Red stars are cooler.
- Blue stars are the hottest.
- White and yellow stars (like the Sun) are moderate in temperature.
- Red stars are cooler.
- Stars differ in brightness, which depends on size, temperature, and distance from Earth.
Lifespan of a Star
- Stars form in nebulae (clouds of gas and dust).
- They go through stages: protostar → main sequence star → red giant → white dwarf, neutron star, or black hole, depending on mass.