Ch 8: Light in Astronomy

Watch online science video lessons to learn about electromagnetic waves, star spectra, the speed of light and more. These lessons are just a portion of our college-level astronomy course.

Light in Astronomy - Chapter Summary and Learning Objectives

Use the lessons in this chapter to discover characteristics of visible light and learn how this region of the electromagnetic spectrum helps us study stars and other celestial objects here on Earth. Instructors explain the basic wave properties and behaviors that allow scientists to disperse the light from stars into spectra used to identify their intrinsic properties, like temperature and chemical composition. This chapter is designed to teach you about:

• Regions of the electromagnetic spectrum
• Wave refraction, reflection, dispersion and diffraction
• Star properties and the appearance of spectra
• Star brightness and the speed of light

Video Objectives
What is Light? Discuss the basic wave properties and quanta of visible light.
The Nature of Light: Origin, Spectrum & Color Frequency Examine the range of visible light found on the electromagnetic spectrum. Study the wavelength of each color frequency.
Electromagnetic Waves: Definition, Sources & Properties Explore frequencies of waves at either end of the visible light range. Identify sources of electromagnetic radiation.
The 7 Major Regions of the Electromagnetic Spectrum Get examples of the electromagnetic spectrum's radio waves, microwaves, infrared radiation, visible light, ultraviolet light, x-rays and gamma rays.
Reflection: Angle of Incidence and Curved Surfaces Describe wave behavior when it strikes a surface. Use the law of reflection to describe the angles of incident and reflected rays.
Resonance: Definition & Transmission of Waves Study the relationship between objects' resonant frequency and the transmission of light or sound waves.
Transparent and Opaque Materials in Electromagnetic Waves Learn how the absorption, reflection or transmission of light waves determines whether an object is transparent or opaque.
Color: White Light, Reflection & Absorption Discover why our perception of color depends on the wavelength of visible light being reflected from an object.
Refraction & Dispersion: Definition, Snell's Law & Index of Refraction Use Snell's law to describe the ratio between the angle of incidence and angle of refraction for a ray traveling through a medium. Explain the dispersion of white light.
Diffraction: Relation to Sound & Light and Effects of Wavelength Describe the behavior of light and sound waves as they bend around barriers or pass through their openings.
Wave-Particle Duality: Concept, Explanation & Examples Explain how the photoelectric effect demonstrates light's behavior as a particle stream.
The Source and Appearance of Spectra Differentiate between the sources of continuum, absorption and emission spectra. Describe their appearances.
Spectra Images & the Emission or Absorption of Light Explore the relationship between atoms' absorption or emission of light and the appearance of spectra.
Intrinsic & Apparent Properties of Stars Distinguish luminosity, chemical composition and other intrinsic star properties from apparent properties, like observed brightness.
Comparing Star Brightness & Color Using the Magnitude System Compare stars' colors and brightness using the magnitude system.
The Speed of Light Explain what a light year is. Use it to describe the relationship between distance and time.

19 Lessons in Chapter 8: Light in Astronomy
Test your knowledge with a 30-question chapter practice test
Chapter Practice Exam
Test your knowledge of this chapter with a 30 question practice chapter exam.
Not Taken
Practice Final Exam
Test your knowledge of the entire course with a 50 question practice final exam.
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