During the past few decades, scientists have discovered smaller sub-

atomic particles that create the electrons,

protons, and neutrons of an atom. As they learn

more about these particles, scientists will

understand the fundamental forces of

nature that cause matter to react the way it does.

The atomic or molecular structure of different substances emits or absorbs unique energy waves. These waves contain electricity and magnetic properties.

These energy waves are referred to as the Electromagnetic Spectrum.

The Electromagnetic Spectrum includes all types of energy waves; some we can hear, cook with, see, and can use to treat injuries and illnesses.

Electromagnetic Waves: Properties of Radiation

• All stars, including our Sun, have EM waves of energy.

• EM waves travel through space.

• EM waves travel through anything.

• EM waves are streams of particles called photons.

• EM waves travel at the speed of light (186,000 miles per second).

Spectrum of Electromagnetic Radiation

Region Wavelength(centimeters)

Frequency(Hz)

Energy(eV)

Radio > 10 < 3 x 109 < 10-5

Microwave 10 - 0.01 3 x 109 - 3 x 1012 10-5 - 0.01

Infrared 0.01 - 7 x 10-5 3 x 1012 - 4.3 x 1014 0.01 - 2

Visible 7 x 10-5 - 4 x 10-5 4.3 x 1014 - 7.5 x 1014 2 - 3

Ultraviolet 4 x 10-5 - 10-7 7.5 x 1014 - 3 x 1017 3 - 103

X-Rays 10-7 - 10-9 3 x 1017 - 3 x 1019 103 - 105

Gamma Rays < 10-9 > 3 x 1019 > 105

Use this diagram of the electromagnetic spectrum to answer the following questions:

Low frequency waves are used to make

profiles of the seafloor.

Observe changes in the elevation along the seafloor

Different Elements Emit Different Wavelengths of the Visible Spectrum:

Mountains

Ocean

Satellites orbiting Earth provide unique images and valuable information about our planet.