Drill 7 1 What is the Sunspot Cycle

Drill #7: 1. What is the Sunspot Cycle? 2. Why do we care about Sunspots?

Objective: SWBAT: Classify stars according to their spectral type.

AGENDA: • LIGHT/EM NOTES • Spectra Demo • Star Spectrum Gizmo

The Electromagnetic Radiation (Light – the Supreme Informant!)

Light Phenomenon • Isaac Newton (1642 -1727) believed light consisted of particles • By 1900 most scientists believed that light behaved as a wave.

The Electromagnetic Spectrum The electromagnetic spectrum represents the range of energy from low energy, radio waves with long wavelengths up to high energy, gamma waves with small wavelengths. https: //www. youtube. com/watch? v=cf. Xzwh 3 Kad. E

The Electromagnetic Spectrum More than meets the eye!

Wavelength • The distance from one wave crest to the next • Radio waves have the longest wavelength and Gamma rays have the shortest!

Visible light is a small portion of this spectrum. This is the only part of this energy range that our eyes can detect. What we see is a rainbow of colors. Red. Orange. Yellow. Green. Blue. Indigo. Violet ROY G BIV

• The colors we see in objects are the colors that are reflected, all other colors are absorbed. • When all colors are being reflected we see white light (white isn’t really a color)

How light or electromagnetic radiation is used in Astronomy • Astronomers use a tool called a spectroscope to separate starlight into its colors – in this way, they can tell what a star is made of, its temperature, luminosity and so on… • Astronomers can look at astronomical objects at different wavelengths…

So how does the electromagnetic spectrum help us study stars?

Spectra of a Star

Blackbody Radiation A black body is a body that is a perfect absorber of light and yet it is a perfect emitter of radiation as well. A star is a gaseous sphere whose surface behaves like a black body.

Blackbody • An object is a "blackbody" if the radiation it emits into space originates completely from its temperature • Blackbody spectra do not depend on an object's chemical composition, its size or its temperature.

• www. explorelearning. com • BDMQMWXZDR • Browse Gizmos: Star Spectra