2. Solar System Notes Measuring Up! Science Lesson 25 Stars

3. California Standards 8.4.b: Students know that the Sun is one of many stars in the Milky Way galaxy and that stars may differ in size, temperature, and color.

4. Language of the Discipline  A star is a ball of hot gases that produces radiant energy by nuclear fusion reactions that occur in its core.

5. Measuring Up! Guided Instruction Read page 165 in the MU book.

6. Guided Questions  How does a star produce energy?  By fusion reactions in which hydrogen atoms fuse to make helium atoms.

7. Measuring Up! Guided Instruction Read the chart on page 165 in the MU book.

9. Guided Questions  How does the HR diagram organize stars?  Stars are organized by brightness, color, and temperature.

10. Measuring Up! Guided Instruction Read page 166 in the MU book.

11. Color Average Temp.Example Apparent magnitude Light years away from Earth Red3,000 o CBetelgeuse0.45427 Orange 4,000 o C Arcturus-0.0536.7 Yellow 6,000 o C Sun-26.730.000016 White 8,000 o C Canopus-0.62312 Blue-White 11,000 o C Rigel0.18773

12. Guided Questions  What is the temperature difference between blue and red stars?  Blue stars are hotter than red stars.  What kind of star is the Sun?  It is a yellow star with a surface temperature of about 6,ooo o C.

13. More Guided Questions  Describe how our Sun compares to other stars.  Our Sun is a medium-sized yellow star with an average temperature. It has a great apparent magnitude but an average absolute magnitude.  Describe all the ways that stars can be different from one another. Why are they different?  Stars are different sizes, colors, temperatures, and magnitudes. They are different because they have different masses and are different ages.

14. Independent Practice: ① Read page 167 in the MU book. ② Complete the Apply questions in your packet. ③ Complete the Assessment Practice in your packet.