P HYSICAL S CIENCE The Electromagnetic Spectrum

O BJECTIVES Explain the properties of the electromagnetic spectrum Differentiate between the different wave types on the Electromagnetic spectrum

Electromagnetic spectrum Electromagnetic waves are transverse waves produced by the motion of electrically charged particles Radiation- the transfer of energy by electromagnetic waves Electromagnetic waves need no medium to transfer energy

Waves travel through each particular medium at the same speed, but their frequencies and wavelengths will change The shorter the wavelength, the greater the wave frequency Photons- tiny massless bundles of radiation Frequency of light corresponds with the energy of the photon

Radio Waves Long wavelength, low frequency Utilized in television, cell phones, and cordless phones Modulation- the process of manipulating radio waves Radio waves with the highest frequency and energy are called microwaves

o Infrared Radiation Given off by the sun Has a wavelength slightly longer than that of visible light The warmer the object, the more infrared radiation given off Infrared waves can be used to warm and dry objects such as food and auto paint

P HYSICAL S CIENCE Electromagnetic Spectrum, part II

Visible Radiation The only part of the electromagnetic spectrum that is visible to us Visible light can be used to stimulate chemical reactions (photo oxidation, photosynthesis, photoreceptors in the human eye, H 2 O 2 decomposition)

Ultraviolet Radiation Has a higher frequency than light, therefore, UV photons are more energetic and have a greater penetrating power Ozone is a combination of three oxygen molecules O 3, and works to filter out harmful rays UV radiation is used to kill germs in food and in hospitals

X-Rays and Gamma Rays X-Rays have a shorter wavelength and higher frequency Higher energy x-ray photons have great penetrating power compared to other forms of electromagnetic radiation This allows x-rays to penetrate human muscle, tissue, and bone

Gamma Rays have the highest frequency of all the electromagnetic spectrum Gamma rays are emitted from the nuclei of radioactive atoms Concentrated gamma rays are used to destroy cancerous cells in humans