Electromagnetic Waves Remember Electromagnetic waves electric and magnetic

Electromagnetic Waves Remember… • Electromagnetic waves: electric and magnetic waves released by a vibrating electric charge, capable of transferring energy through a vacuum. – Do not need a medium to travel through. • Instead of transferring energy from particle to particle like mechanical waves, they transfer energy between electric and magnetic fields, which can exist with or without matter. – All electromagnetic waves travel at a speed of 300, 000 m/s in a vacuum. • They slow as they travel through matter.

Waves vs. Particles Remember… • Waves: a disturbance that can carry energy. • Particles: pieces of matter. • Electromagnetic waves can behave as waves and as particles, called photons. – Photon: massless bundle of energy.

Electromagnetic Spectrum • Electromagnetic waves give off energy in the form of electromagnetic radiation. – There is a broad range in the different types of EM radiation. • Electromagnetic spectrum: the entire range of frequencies of electromagnetic radiation.

Electromagnetic Spectrum ROYGBIV Longer wavelength Lower frequency Lower energy Shorter wavelength Higher frequency Higher energy

Electromagnetic Spectrum • Radio waves: emitted by radio stations, MRI’s, RADAR, Wi-Fi, TV, and cell phones. – Longest wavelength with the lowest frequency.

Electromagnetic Spectrum • Microwaves: used for cooking, Doppler radar, and GPS.

Electromagnetic Spectrum • Infrared waves: used in night vision goggles, remote controls, and infrared photography.

Electromagnetic Spectrum • Visible Light waves: the only electromagnetic waves we can see; given off by the sun and light bulbs. – Different colors of light have different wavelengths. • ROYGBIV – red is the longest and violet is the shortest.

Electromagnetic Spectrum • Ultraviolet waves: given off by the sun; used in light bulbs, to kill bacteria, and by the human body to make vitamin D.

Electromagnetic Spectrum • X-Rays: used to take pictures of bones to check for breaks and fractures, also used in CAT scans. – Small enough to penetrate skin cells. • Overexposure can cause cancer.

Electromagnetic Spectrum • Gamma Rays: used to kill cancer cells, sterilize medical equipment, and in radioactive tracers. – Smallest wavelength with the highest frequencies.