Chapter 1. The Nature of Light

Overview

Astronomers are passionately interested in the nature of light because it is the only information we get from stars. The stars, and most of the planets for that matter, are so far away that we will probably never visit them. So, for now, astronomers must learn to decode information hidden in starlight if we are to learn anything at all about the nature of these distant objects. Fortunately, the properties of light are well understood. After starlight is split into a rainbow by passing it through a prism or similar device, careful inspection of the light provides detailed information about the temperature, composition, and motion of stars.

Drawing of Newton's experiment showing that colors do not come from the glass of a prism. The second prism undoes the effects of the first prism, rather than adding more color, which it should if the prism creates the color.

Observation

Question Nature of Light and Matter

When a beam of white light passes through a glass prism, the light is broken into a rainbow-colored band called a spectrum. The numbers on the right side of the spectrum indicate the wavelengths of different colors of light.

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Tutorials

Introductory text for tutorials.

...Light and Temperature (L2 section)

......Nine subsections of content go here.

...Spectroscopy (L2 section)

......subsections of content go here.

Activities

Introductory text for activities.

...Light and Temperature (L2 section)

......Java Wavelength Calculator app and questions go here.

...Spectroscopy (L2 section)

......Java Doppler app and questions go here.

Examination

Introductory text for 20 questions that follow.