Transcript Document

Light, Reflection, and
Refraction
Today we will
investigate and explore
properties of light and light transmission
using lasers and LED flashlights.
What do we know about light?
Properties of Light
Light travels in straight paths:
Laser
Light travels VERY FASTaround 300,000 kilometers per
second.
At this speed it can
go around the world
8 times in one
second.
Light travels much faster than sound.
Thunder and lightning
start at the same time,
but we will see the lightning
first.
• We see things because they
reflect light into our eyes:
Homework
What happens when light hits an object?
Law of Reflection
When a ray of light is reflected from a
smooth surface, the angle of reflection
is equal to the angle of incidence.
Normal Line
Law of Reflection
When a ray of light is reflected from a
smooth surface, the angle of reflection
is equal to the angle of incidence.
REFRACTION
Light slows down and bends as it passes
through substances of different densities.
Refraction
What’s going on? Is the
ruler really bent?
What about here?
REFRACTION
Fiber Optics
Light passes through objects in varying amounts.
Transparent
Translucent
Opaque
Light travels much faster than sound.
Light reflects-we see things because they
reflect light into our eyes.
Light travels in straight lines.
Light refracts.
Light is transmitted.
Moth eyes
Anti-reflective coating
Scientists are trying to make an anti-reflective coating as good
as a moth’s eye.
Going Green with LED
-LED light bulbs are energy efficient.
-An LED light bulb can last you up to 30,000 hours.
- LED light bulbs are directional.
-LED light bulbs run cool.
LEDs turn on instantly.
LEDs do not use mercury like CFLs .
Recent studies suggest that the light
produced by LED light bulbs can help
people stay more alert.