1. How Light Spreads Out Lesson 4

2. What’s the deal? The Sun is one medium size star. The Andromeda Galaxy is a cluster of hundreds of billions of stars*, most are larger than the Sun. Why is the Sun so incredibly much brighter than the whole Andromeda Galaxy? *710,000,000,000 solar masses according to Wikipedia.

4. What should I put in my data table?

5. Ideal Data (Don’t Change Yours) Distance from Light Source Area of Illumination (Lit Area) 10 cm1 cm 2 20 cm4 cm 2 30 cm9 cm 2 40 cm16 cm 2 50 cm25 cm 2

6. What kind of graph should we use?

7. Extrapolating: Estimating beyond the measured/recorded data. Distance from Light Source (cm)

8. Exponential Relationship

9. Formula: Area of Illumination = (Distance to Light Source/10) 2 y=(x/10) 2 Where y=Area of Illumination and x=Distance to the Light Source Big idea: As light leaves the source the light spreads out and becomes weaker (less energy) exponentially.