What do you know about light? Think – Pair - Share

Light can be Luminous – object that emits (gives off) their own light. (ex. Sun) or Nonluminous – object that do not emit light, but only reflect light from other sources.

Light from Incandescence The process of emitting light because of a high temperature is incandescence. Example: Incandescence light bulb

Light from Phosphorescence The process of emitting light for some time after receiving energy from another source. Example: Glow in the dark watch

Light from Electric Discharge The process of emitting light because of electricity passing trough a gas. Example: Neon sign

Light from Fluorescence The process of emitting light while receiving energy from another source. Example: fluorescent light bulb

Light from Chemiluminescence The process of changing chemical energy into light energy with little or no change in temperature.

Light from Bioluminescence Some living things can make themselves luminous using chemical reaction similar to chemiluminescence. Example: Fireflies, glow worms

Light Light can be: Natural – bioluminescence, stars, sun, moon Electric – incandescent light bulbs, flashlights and electroluminescence (LED) Chemical – chemiluminescence (glow sticks), fluorescence (fluorescent light bulbs) and phosphorescence (glow in the dark materials) Combustion-based – candles, fire, torches Nuclear

What are some technologies based on properties of light? microscope telescope periscope binoculars fiber optics camera prescription contact lenses laser movie projectors overhead projectors etc.

The History of Light Pythagoras (born between 580 and 572 BC, died between 500 and 490 BC) A Greek mathematician and philosopher.

He believed that beams of light were made up of tiny particles. When these beams of light came from objects and reached the eye, they carried information about the object to the eye.

Albert Michelson ( ) An American physicist known for his work on the measurement of the speed of light. In 1907 he received the Nobel Prize in Physics, the first American to receive the Nobel Prize in sciences.

Early Technologies One of the earliest technologies involved using light to improve vision. This was a curved piece of glass which enlarged print. Today we call this a magnifying glass

This technology eventually led to glasses. Then (1200)Now

Anton van Leeuwenhoek ( ) He is commonly called the “Father of Microbiology” He was the first person to observe and describe single celled organisms.

Microscope He created over 400 types of microscopes after he discovered that he could increase the magnifying power of a lens by increasing its curvature. 1 st compound microscope Leeuwenhoek microscope Now Then

Galileo Galilei ( ) He made his own lenses which he used to build a telescope to magnify objects in space. He discovered four of Jupiter’s moons. Galileo’s early telescope