Energy Unit
Week 34
Directions
1.Prepare your desk for science.
• Science notebook
2.Use voice level 0 (no voice) to review your light
energy notes from notebook pg. 83.
Targets & Warm Up
Targets:
• Students will understand how light can
be reflected, absorbed, or refracted.
Warm Up: How does light travel?
How does light travel?
Light travels in straight lines called __________
rays
that fan outward from the source of light.
BUT
Light can change when it strikes (hits) an object.
• Reflect
• Absorb
• Refract
Table of Contents
Date
5-19-15
Title
Behavior of Light
Page
84
Once you are finished with the Table of Contents,
go to page 84 and add the title and date to the
top of the page.
Reflection
• Occurs when light waves bounce, or reflect,
from a surface back to our eyes
• Some objects reflect more light rays than
others
Absorption
• Occurs when an object takes in the light wave
• After a light wave is absorbed, it becomes a
form of heat energy
Color and Light
• We see colors because objects reflect and
absorb light.
• An object is a certain color because it absorbs
all colors except for the color that it reflects
back to our eyes.
Color and Light
Reflect? Absorb?
Color & Light
What color is reflected? What color(s) are
absorbed?
Reflected: Red
Absorbed: All
other colors
Reflected: None
Absorbed: All
colors
Reflected: All
colors
Absorbed: None
Letting Light Through (Transmission)
• Transparent: Let
most light rays pass
• Translucent: let
some light rays pass
• Opaque: Do not let
any light rays pass
How Light Changes Direction
• Light travels fastest through outer space
where there is no matter
• Light slows as it travels through various
mediums
– Travels slowly in a gas
– Travels more slowly in a liquid
• When light moves at an angle from one
medium to another, some light…
– Is reflected or absorbed
– Passes through and changes directions (bends)
Refraction
• The bending of light caused by the change of
speed that occurs when the wave passes
from one medium into another
Light travels from the
pencil through water,
though a glass, and
through the air to
your eye
Refraction
Lenses
• Lenses are curved pieces of
clear glass or plastic that
refract light that passes
through them
• Two types:
– Concave
– Convex
Convex Lens
• Thicker in the middle
than at the edges
• Light rays bend in
toward the middle of
the lens
• Makes things appear
larger
• Found in magnifying
glasses and microscopes
Concave Lens
• Thinner in the middle
than at the edges
• Light rays bend out and
spread apart
• Makes things appear
smaller
Telescopes
Concave and convex lenses are
often used together to make
details look sharper
StudyJams Video
Light absorption, reflection, and refraction
http://studyjams.scholastic.com/studyjams/jam
s/science/energy-light-sound/light-absorbreflect-refract.htm
Extra Time?
Pretend that you are shining a flashlight on
these objects. Do the objects reflect, absorb, or
refract light?
Reflection Questions
• What is reflection? What is absorption? What is
refraction?
• What are some examples of when light is
reflected, absorbed, or refracted?
Homework
Targets (Revisited)
• Students will understand how light can be
reflected, absorbed, or refracted.
Homework
Subject
Science
Homework
Light Energy worksheet
Due Date
Wednesday
(tomorrow)