Transcript Light! - Weebly

Light!
Before we begin…
• Our class time in here will be similar to when we
had the animals: we will need to direct our
attention to the SmartBoard first, then break off
into stations and activities.
• There will be no science journals!
• If you choose not to cooperate you will be
answering questions from books at the front or
worksheets with the science textbook.
What questions do we have
about light and electricity?
• Write a question on a slip of paper and put
it in our question box.
• We will draw 2 questions each day to
answer.
What is light?
• Light is a form
of ENERGY.
- Energy is the
ability to make
something move,
happen or change.
What is light?
• Light is made up
of many different
COLORS.
- The different colors
appear when white light
is passed through a
prism separated into a
spectrum.
- The colors represent
different amounts of
energy.
The colors of the visible light spectrum
wavelength
interval
frequency interval
red
~ 700–635 nm
~ 430–480 THz
orange
~ 635–590 nm
~ 480–510 THz
yellow
~ 590–560 nm
~ 510–540 THz
green
~ 560–490 nm
~ 540–610 THz
blue
~ 490–450 nm
~ 610–670 THz
violet
~ 450–400 nm
~ 670–750 THz
color
Types of light
Visible light is the light that humans can see. Other
animals can see different types of light. Dogs can see
only shades of gray and some insects can see light
from the ultraviolet part of the spectrum. The key
thing to remember is that our light is what scientists
call visible light.
In order for an object to be visible, it must either:
1. Give off its own light ( sun, candle, flashlight)
OR
2. REFLECT light
Seeing light
The visible light you see is
the light that is NOT
absorbed by objects.
Green plants for example,
are green because they
absorb all of the colors of
the visible spectrum
EXCEPT the green color.
Review
Study Jams Clip
• http://studyjams.scholastic.c
om/studyjams/jams/science/
energy-light-sound/light.htm
Today we will:
Separate sunlight into the
colors of the spectrum!
You need: Pencil
Jacket
Prism
“Prism Play” Sheet
How Light
Travels through
objects
• A transparent material allows light to pass
through it because it is not absorbed or
reflected.
• Objects can be seen clearly when viewed
through transparent materials.
Air, glass, and water are examples of
materials that are transparent.
examples
Light passes through air
clearly.
Water allows light to pass
through easily.
Light bulbs are made of
glass
• A translucent material scatters or absorbs
some of the light that strikes it and allows
some of the light to pass through it.
• Objects appear as blurry shapes when
viewed through translucent materials.
Waxed paper and frosted glass are
examples of materials that are translucent.
Wax paper does not
let light pass through
easily.
Frosted glass does
not let light pass
through easily.
• An opaque material does not allow light to
pass through, light is either reflected from
or absorbed by an opaque material.
Wood, metals, and thick paper are examples
of materials that are opaque.
Light cannot pass
through wood like a
baseball bat.
Light cannot pass
through Cocky.
Light cannot pass
through a football.
Light’s Primary Colors
• The human eye
recognizes color using
photo receptors called
cones, which are located
in the retina of each eye.
• There are 3 types of
cones that are each
sensitive to 1 of the 3
primary colors of light –
red, blue, green.
Light’s Primary Colors
Red
Blue
Green
(NOT Yellow)
Today we will…
• Rotate at two different stations:
One will be using the primary colors of
light with flashlights and the “Colortime
Theatre” worksheet.
The other will be identifying opaque,
translucent, and opaque materials using
a flashlight as a source of light and
recording your findings.
Combining the primary colors of
light produces…
Cyan
Yellow
Magenta
http://www.teachersdomain.org/asset/
lsps07_int_lightpigment/
How Light
strikes objects
How light strikes objects
• When light hits an object, the light will
either:
• bounce off (reflection),
• change direction (refraction),
or
• not reflect or pass through (absorbed).
• http://www.kids-scienceexperiments.com/cat_absorption.html
Reflection
•When light is reflected, it bounces
back from a surface.
•Reflection allows objects to be seen
that do not produce their own light.
Reflection
•When light strikes a
smooth, shiny object, a
mirror, or a pool of water,
it is reflected so that a
reflection can be seen that
looks very similar to the
object seen with light
reflected directly from it.
Refraction
• When light is refracted it passes from
one type of transparent material to
another, and changes direction. For
example, when light travels through a
magnifying glass, it changes direction,
and we see a larger, magnified view of
the object.
Refraction
•When a pencil is viewed
in water, light passes
from the water to the air
causing the path of the
light to bend. When the
light bends, the pencil
appears distorted (bent
or broken)
Absorption
• When light is absorbed it does not pass through or
reflect from a material. It remains in the material as
another form of energy.
• The colors of objects are determined by the light that is
not absorbed but is reflected by the objects.
• All other colors of light striking the object are absorbed
by the object.
• A red object, for example, reflects red colors of light and
absorbs all other colors.
• http://studyjams.scholastic.com/studyjams/
jams/science/energy-light-sound/lightabsorb-reflect-refract.htm
Reflection Station
Reflection Station
Absorption Station
Refraction Station