What do you know about light? Think – Pair - Share
Dec 28, 2015
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 (1852-1931)
• 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 (1632-1723)
• 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.
1st compound microscope
Leeuwenhoek microscope
NowThen
Galileo Galilei (1564-1642)
• 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