# Introduction to Light

## Physical Science - Middle School

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photons Einstein electrons Introduction To Light c (speed of light ) = 300, 000 km/s electrical eld electromagnetic waves magnetic eld c = wavelength (λ) x frequency ( ν) Electromagnetic Waves What surrounds you and bombards you constantly? Most of it is invisible but you can’t imagine living without it. It is electromagnetic radiation, a type of energy commonly known as light. This energy is produced by the vibration of charged particles. 2:13 1 2 3 4 5 6 7 8 9 0 1 + - - + 2 3 4 5 6 7 8 9 0 M 2 M 2 C 1 GH I PQR S As charged particles move back and forth, the electric field around them vibrates, creating a vibrating magnetic field. The two vibrating fields, which are at right angles to each other, produce electromagnetic waves. These waves can travel through materials as well as a vacuum. All electromagnetic waves travel at the incredible speed of about 300,000 km/s in a vacuum, often called the speed of light. This speed is equal to the wavelength of light times its frequency and is represented by the equation c = wavelength x frequency. Light: Wave or Particle Most of us think of light as a wave. Waves easily explain interactions such as reflection. However, early in the 20th century, some scientists noticed that light hitting a metal surface can sometimes eject electrons. How can light waves do this? Albert Einstein showed this can only happen if light is made up of tiny particles called photons. Einstein revolutionized physics by describing light as photons. Scientists now believe light exhibits both wave and particle properties. © Copyright NewPath Learning. All Rights Reserved. 94-4476 Visit www.newpathlearning.com for Online Learning Resources.
Introduction To Light Pause and Review Complete the graphic organizer. © Copyright NewPath Learning. All Rights Reserved. 94-4476 Visit www.newpathlearning.com for Online Learning Resources. Electromagnetic Waves produced by known as made up of explain the interaction travel at a speed of represented by the equation