## The Electromagnetic Spectrum

Each activity or resource is labeled by access mode:

Main Topics & Concepts
• Light can be modeled as a wave; waves have certain properties; such as wavelength and frequency. Appropriate unit is the Ångstrom
• Visible light is a small part of the EM spectrum, which spans many decades in wavelength
• Light energy is inversely proportional to wavelength, proportional to frequency.
Standards
This topic applies to California state standards 4a, 4c and 4e in 9th grade Earth Science.

Science Probe Text
Science Probe II § 7,1 Electromagnetic Radiation

Activities & Lessons
Activity Access Description

SEGway**

Students access an interactive tool that returns a spectral region given a wavelength in Angstroms.  They use this tool to find the limits of regions of the EM spectrum and chart them to show the "complete" spectrum.  The Web site has material about wave basics, the scales of wavelengths, from atomic to kilometers, an  astronomy image gallery, and a light type search puzzle.

Xray Spectroscopy and the Chemistry of Supernova Remnants Part II: What is Electromagnetic (EM) Radiation? How is it produced in atoms? What Units are used to characterize EM radiation?

NASA/Imagine the Universe!

Despite the Guide's overall title, Part II uses supernova remnants as a case in point to introduce students to the EM spectrum and the idea that different wavelengths/frequencies carry different amounts of energy. Covers quantized energy absorption and emission by atoms.

Access the desired sections of Part II from the guide's outline page.

Students will need some basic knowledge of chemistry and scientific notation.

Point of View
Chandra Education/Outreach
Small groups of students use images in x-ray, infrared, radio and optical to describe one of two supernova remnants. Some interpretive material is also linked to the images. Descriptions may be presented as talks to the class, jigsaw-style.
Frequency, Wavelength, and Energy Activity

X-ray Timing Explorer Learning Center

Nice illustration of unit conversion, a technique students will use throughout physical science. Easily printed out as a reading/worksheet. Introduces the quantum equation for photon energy using Planck's Constant, but doesn't go into photons. Teachers may need to explain the idea of a unit of energy (erg)

J-5 Seeing the Invisible: Studying Infrared and Ultraviolet

ASP*

Students do recreations of experiments that demonstrate the existence of radiation beyond the red and violet ends of the visible spectrum.

J-11 FIngerprinting the Cosmos: Using Colored Filters in Astronomy

ASP*

Students use colored filters to examine slides of stars and nebulae. The filters allow them to distinguish stars of different temperatures and nebulae with different compositions. Requires a slide set (available from ASP) and colored filters.

*Astronomical Society of the Pacific Ordering info \$\$

**Science Education Gateway

Resources
Resources Access Description
Spectra of Gas Discharges

Laser Stars/ Plasma Laser Astrophysics

Very handy if you don't have access to lots of discharge tubes and spectroscopes. This applet produces JPEG images of what elemental gas discharges look like "in a good visual spectroscope."

Hubble Space Telescope

Java applet that lets students vary the "energy" of a wave and measure the frequency and wavelength.  The applet checks their entered values.
Infrared

NASA/SECEF***

This 24 Mg video explains the difference between infrared and visible light, and the connection between infrared emission and temperature, through everyday and astronomical examples. Down load well in advance, as the QuickTime file is large.
Shedding New Light on the Universe

X-ray Timeing Explorer Learning Center

A narrative beginning with basic properties of the EM spectrum, going on through ideas of non-visible light (x-rays), multi-wavelength astronomy, and much more. Learning activities are interspersed. Sections up through the "Crab Nebula at Different Wavelengths" touch on this topic.
A Tutorial on the Infrared Sky

NASA/GSFC

Describes pervasive infrared radiation in the sky using images from the DIRBE instrument on the Cosmic Background Explorer satellite. Introduces Wien's Law, a basic relationship between emission spectrum and temperature.

***SECEF: Sun-Earth Connection Education Forum