The Electromagnetic

Spectrum

How would you describe the color

of light that comes from the

Sun?

• Visible light can be broken into component wavelengths by using a prism

VISIBLE LIGHT

• Sun - the main source of energy on Earth

• Energy - the ability to do work

• Electromagnetic Energy - transverse waves that transmit energy through space

Waves animation

Electromagnetic Spectrum - the entire range of electromagnetic wavelengths

• All wavelengths travel through space at 3.0 x 108 m/s (speed of light)

Wavelength - the distance between two successive crests or troughs

Waves animation

Longwavelength

Shortwavelength

• Frequency - the number of waves that pass a certain point in a given period of time

• Frequency depends on wavelength - the longer the wavelength, the lower the frequency

1 minute

The Electromagnetic Spectrum

Radio Waves

This Doppler-radar image seen on TV weather news uses microwaves for local weather forecasting. Shown here is Hurricane Claudette's eye-wall making landfall. Credit: NOAA

Microwaves

Infrared Waves

Infrared Waves

A typical television remote control uses infrared energy at a wavelength around 940 nanometers. While you cannot "see" the light emitting from a remote, some digital and cell phone cameras are sensitive to that wavelength of radiation. Try it out!

Most of the new stars cannot be seen in the visible-light image (left) because dense gas clouds block their light. However, when the pillar is viewed using the infrared portion of the spectrum (right), it practically disappears, revealing the baby stars behind the column of gas and dust.

Infrared Waves

INFRARED FILMColor Infrared film can record near-infrared energy and can help scientists study plant diseases where there is a change in pigment and cell structure.

Bees, along with some birds, reptiles and other insects, can see near-ultraviolet light reflecting off of plants. Bug zappers attract insects with ultraviolet light to lure them to the trap.

Ultraviolet Waves

X-rayWaves

NASA's Swift satellite recorded the gamma-ray blast caused by a black hole being born 12.8 billion light years away (below). This object is among the most distant objects ever detected.

Gamma rays also stream from stars, supernovas, pulsars, and black hole accretion disks to wash our sky with gamma-ray light.

Radiowave Microwave Infrared

Visible Ultraviolet X-Ray

Some wavelengths of electromagnetic energy can travel through our atmosphere, and others cannot.