Properties of light

Learning goals We are learning the properties of light. We are learning the components of the electromagnetic spectrum.

Basic properties of light 1. Light travels at tremendous speed. c = 3.0 X 108 m/s (299 792 458 m/s) 300 Earth diameters per second

Fun facts The Earth to the Moon: 1.255 seconds The Sun to Earth: 8.3 minutes Our Sun to the next closest star: 4.24 years Across our Milky Way galaxy: 100,000 years To the closest spiral galaxy (Andromeda): 2.5 million years Limit of the observable universe to Earth: 13.7 billion years

Basic properties of light 2. Light travels in straight lines Linear Propagation Light radiates in all directions from a luminous object Radiation: method of energy transfer that does not require a medium; energy travels at the speed of light

Basic properties of light 3. Light travels as waves Although light travels in straight lines, individual photons (bundles of energy) travel as waves Compare to a care traveling along a straight road Electromagnetic waves

Since light travels as waves Many waves of energy of different wavelengths can travel together Some wavelengths are visible to the human eye and others are not Each colour we see is a different wavelength

Electromagnetic spectrum

Learning goals We are learning the properties of light. We are learning the components of the electromagnetic spectrum.