Download Light Week 5 - SharpSchool

Light Week 5
Properties of Light
Lenses and Optical Tools
Eye Structure and Function
Catalyst
1. What is the law of reflection?
2. A light ray hits a mirror with a 40 degree
angle of incidence--what is the angle of
reflection?
3. What is the difference between
reflection and refraction?
4. What is the difference between diffuse
reflection and regular reflection?
Property # 1: Reflection
Reflection
happens when
light bounces
off of an
object.
Reflection Practice Problems
Property #2: Absorption
Absorption is the
transfer of light
energy to its
surrounding
environment.
Ex: Hot window on a
warm day
Ex: The reason why a
flashlight beam gets
dimmer is because the
light gets absorbed by
air particles.
Property #3: Scattering
Scattering is the
release of light
energy in all
directions.
Ex: Sunlight
Blue light is
scattered the most
by sunlight, which
is why the sky looks
blue.
Property #4: Transmission
Transmission
happens when light
waves strike
something and
passes through it.
When you see
through glass, it is
because light is
able to pass
through the glass.
More on Transmission
Types of objects
Transparent (light transmitted)
Translucent (some light transmitted)
Opaque (no light transmitted)
Stand Up For Your Light!
WHEN LIGHT BOUNCES OFF AN
OBJECT
REFLECTION
TRANSFERS LIGHT ENERGY TO THE
SURROUNDING ENVIRONMENT
ABSORPTION
RELEASE OF LIGHT IN ALL
DIRECTIONS
SCATTERING
TRANSMISSION
& ABSORPTION
OCCURS WHEN LIGHT STRIKES A
MATERIAL AND PASSES THROUGH
IT
TRANSMISSION
TRANSMISSION
SCATTERING
REFLECTION
ABSORPTION
ABSORPTION
TRANSMISSION
REFLECTION
SCATTERING
REFLECTION
Bill Nye: Light Optics
Take notes for EC!
Exit Quiz
What is the difference between
transmission, absorption, and
scattering?
Name one real world example for
each of the four properties of light.
I Can…
I CAN describe the 4 properties of
light
Reflection
Absorption
Scattering
Transmission
Catalyst: Period 3
1. What is the law of reflection?
2. A light ray hits a mirror with a 40 degree angle
of incidence--what is the angle of reflection?
3. What is the difference between reflection and
refraction?
4. What is the difference between diffuse
reflection and regular reflection?
5. What are the 4 properties of light?
Catalyst: Period 4
Define each of the four properties of
light. Give a real world example of
each.
I Can…
I CAN describe and compare and
contrast convex and concave lenses.
I CAN describe how lenses are used
in optical tools
Microscopes
Cameras
Telescopes
Lens
A lens is a
curved piece
of glass or
other
transparent
material that
refracts
light.
Focal Point and Optical Axis
OPTICAL AXIS: An imaginary line
that divides a lens or mirror in half.
FOCAL POINT (F): The point where
light rays parallel to the optical axis
converge (come together).
Lens and Images
A lens forms an image
by REFRACTING light
rays that pass through
it.
The type of image
formed by a lens
depends on the shape
of the lens and the
position of the object.
Types of Images
VIRTUAL IMAGE:
upright image that
forms where light
seems to come
from (like a
mirror)
REAL IMAGE:
forms when light
rays actually meet.
(appears upside
down).
Types of Lenses
There are 2
types of
lenses:
1. CONVEX
2. CONCAVE
Convex Lens
A convex lens or magnifying glass is
thicker in the center than at the
edges.
Convex Lenses
A convex lens can focus the light that
enters it and direct it to one point.
Convex Lenses and Images
Depending on where you hold the
lens--the image you see will either be
right side up (real image) or upside
down(virtual image)
Examples of CONVEX lenses
1. Magnifying glass
2.Cameras
3.Telescopes
4.Our Eyes
Concave Lens
A concave lens is thinner in the
middle than at the edges
It looks like there is a cave
on both sides!! So, it must
be concave!!
Concave lenses
Concave lenses make light rays move away
from each other or spread out.
Concave Lenses and Images
A concave lens produce upright
images that are smaller than the real
object.
Example of CONCAVE lenses
Nearsighted eyeglasses
(can’t see far away)
Optical Tools
Using lenses in the REAL world
Camera
LENS: focuses light.
SHUTTER:
controls
whether light
reaches film.
APERTURE: controls
how much light
enters.
• A camera uses one
or more lenses to
focus light, and
film to record an
image.
• The lens of a
camera focuses
light from the
object to form an
upside-down image
on the film in the
back of a camera.
Telescopes
A telescope forms enlarged
images of distant objects.
Telescopes use combinations
of lenses or mirrors to
collect and focus light from
distant objects.
Two types: REFLECTING
and REFRACTING
Microscopes
A microscope
makes small
objects look
larger.
A microscope uses
a combination of
lenses to form
enlarged images of
tiny objects.
Exit Quiz
What is the difference between
convex/concave lenses?
Describe any two optical tools you
learned about today.
Catalyst
Why is the eye important?
How do you think it works?
Why would we be studying the eye in
a unit on Light?
I Can…
I CAN identify the parts of and the
function of the eye.
Vocabulary:
Cornea
Pupil
Iris
Retina
Rods
Cones
Lens
Optic Nerve
Ligaments
Aqueous humor
Vitreous humor
Nearsighted
Farsighted
Analogy: The Eye as a Camera
HOW DOES A CAMERA WORK?
1. Light enters the camera
through the aperture
2. The lens (glass part)
focuses the light.
3. The shutter lets the light
pass through to the film
(the black part that opens
and closes when a picture
is taken).
4. The focused light creates
an image on film.
Analogy: The Eye as a Camera
Basically, a camera lets in a certain
amount of light, focuses the lights, and
prints the image that the light creates
onto film.
Analogy: The Eye as a Camera
 The eye is like
a camera. It
also lets in a
certain amount
of light,
focuses the
light, and
creates an
image.
1. Cornea
 Clear outer tissue that covers the eye
(column A)
1. Cornea
 Receives light that is reflected by an
object (column B)
1. Cornea
 Analogy to the camera: Lens (Column D)
 The cornea is like the outer lens because
it receives light and sends it to where it
needs to go
2. Pupil
 Round black hole behind the cornea
(column A)
2. Pupil
The pupil lets light into the eye (column
B)
2. Pupil
 Analogy to the camera: Aperture (Column
D)
 The pupil is like the aperture because it
helps to control how much light enters
the eye.
3. Iris
 The colored part surrounding the black
pupil (column B)
3. Iris
Opens and closes the pupil to control the
amount of light coming through
3. Iris
 Analogy to the camera: Shutter
(Column D)
 The iris is ALSO like the shutter
because it helps to control how
much light enters the eye.
4. Lens
 Clear tissue behind the pupil and iris
4. Lens
 Collects and focuses light
Calf eye lens
4. Lens
Analogy to the camera: Lens (Column D)
The lens of the eye is ALSO like the lens
of a camera because it receives light
(from the pupil) and focuses the lights.
Vitreous fluid
 Fluid-filled space between the lens and
the retina
Vitreous fluid
 Gives the eyeball its round shape
Vitreous fluid
 Analogy to the camera: Empty space
between the lens and the film
(Column D)
 The vitreous fluid is the empty space
between the lens and the film
because that is the space that light
needs to travel through to reach its
final destination.
5. Retina
 A thin layer of tissue at the back of the
eye that has light-sensing cells called
rods and cones
5. Rods
Rod-shaped
work in dim light
let you see black,
gray, and white
5. Cones
cone-shaped
work in bright light
let you see color
Investigate: After-Images
Quic kTime™ and a
TIFF (Unc ompres sed) decompress or
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this pict ure.
Investigate: After Images
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
After-Images: Explained
The ghostly birds are called afterimages.
An afterimage is an image that stays
with you even after you have stopped
looking at something.
As you stare at the red bird, lightsensitive cells at the back of your eyes
become less responsive to red light.
When you shift your gaze to the
birdcage, your visual system subtracts
red light from the white light that is
being reflected from the white
background.
White light minus red light is blue-green
light. That is why the afterimage of the
parrot is blue-green.
6. Retina
 Analogy to the camera: Film
(Column D)
 The retina is like the film because
this is where light produces a
rough image (but not the final
image!)
7. Optic Nerve
 Located at the back of the eye
7. Optic Nerve
 receives electrical signals from the
retina
 sends them to the brain where the final
image is made
7. Optic Nerve
Analogy to the camera: Journey that you
walk when you take your film to the lab
to get developed (Column D)
The optic nerve is the journey because
this is the path that the light/electrical
signals take to become a final picture!
The brain is like the lab that develops
the picture.
Wow, that was a lot of info!
Quick review:
 A camera takes in light, focuses
light, and creates an image.
 An eye is like a camera because it
also takes in light, focuses light, and
creates an image.
 Light travels through the cornea,
pupil, iris, lens, vitreous space,
retina, and optical nerve.
Brain POP
The Eye
Parts of the Eye
Scrambler
Cow Eye Dissection
Virtual
Eye Model
Exit Quiz
 What are the seven parts of the eye
that light hits in order?
 How does the eye act like a camera?