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Speed of Light

The speed of light is much greater than the speed of sound.

      Olaus Roemer --- Danish Scientist, 1st method to find the speed of light, used the planets, he calculated the speed of light was 227,000 kilometers per second

      Albert A. Michelson --- 1926, developed a more modern method to determine the speed of light, used mirrors, calculated the speed of light to be 186,285 miles per second (299,796 kilometers per second)

The wavelength of any electromagnetic vibration x its frequency = the speed of the electromagnetic vibration

Scientists have determined that the speed of any electromagnetic vibration = the speed of light (approximate value of the speed of light is 300,000 kilometers per second)

The speed of an electromagnetic wave is not affected by temperature, but it is affected by the medium through which it travels.

Transmission of Light

Light can travel through a vacuum.

      Opaque Objects --- completely block light and through which you cannot see

      Transparent Objects --- readily transmit light and through which you can see clearly

      Translucent Objects --- allow light to pass through partially or that distort the light so that you cannot see through them

Behavior of Light

Light travels in a straight line.

      Pinhole Camera --- the object that is viewed is upside-down

      Shadow --- the dark space behind an object that is formed when light is blocked by that opaque object

      Umbra --- the darker central portion of the shadow that receives no light from the source

      Penumbra --- the lighter shadow that surrounds the umbra and receives some light from outer edges of the light source

Presented By: Mary