The Electromagnetic Spectrum, Visible Light & Us

The Electromagnetic Spectrum, Visible Light & Us

How do we see what we see??

Essential Standard

• 6.P.1 Understand the properties of waves and the wavelike property of energy in earthquakes, light and sound waves.

Clarifying Objective

• 6.P .1.2Explain the relationship among visible light, the electromagnetic spectrum, and sight.

Essential Questions

• What part of the Electromagnetic Spectrum is VISIBLE LIGHT?

• What causes light to appear as different colors?

• What type of WAVE does light energy travel on?

• What is the process of light being detected by the human eye?

EOG Questions

• What is the relationship between EYESIGHT & LIGHT?

• What is the relationship between the Electromagnetic Spectrum & Eyesight?

Light & How we See

• http://www.youtube.com/watch?v=gtgBHsSzCPE

• 1:25-4:04

Essential Questions

• Get with a partner and answer…

• What causes light to appear as different colors?

Waves• Waves are a disturbance or

vibration a way of transferring ENERGY from one place to another

• They transport ENERGY from on place to another

• There are different categories & types of waves

• They all have their own characteristics that make them waves

Light Waves• Light is Photon ENERGY

that travels through WAVES

• These waves are Electromagnetic Waves

• These Electromagnetic Waves create the Electromagnetic Spectrum

Photons• Photons are particles that have a

0 mass

• Electromagnetic waves are carried through the electromagnetic spectrum by photons

• These photons can move through mediums but do not need to

• They can pass through vacuums

How Photons are made

• Photons occur from atoms

• Atoms are made of protons, neutrons & electrons

• Electrons orbit around the nucleus

How Photons are made• When an electromagnetic charge

occurs the electrons of the atom get excited and start moving faster

• When they move faster the electrons move out of their regular orbit into an outer orbit

• When they stop moving faster they drop back down into their regular orbit

• When they drop down they create/make a photon

• This is what we see

Electromagnetic Waves• Electromagnetic Waves are waves

that wave through electromagnetic fields

• These are the only waves that do not require a medium to travel through

• Transversal Waves

• http://www.youtube.com/watch?v=d50avTf0OLw

• 4:00-4:34

Electromagnetic Spectrum• The Electromagnetic

Spectrum is made up of 6 different kinds of Electromagnetic waves

① Radio Waves② Microwaves③ Infrared Waves④ Ultraviolet Waves⑤ X-Ray Waves⑥ Gamma Waves

Electromagnetic Spectrum

Electromagnetic Spectrum• Each of these 6 waves has a

different frequency

• The more to the right on the spectrum you go the higher the frequency of the wave

• The higher the frequency the more energy the wave is carrying

Wave Frequency• The Frequency of a wave is

how many waves are in a given space

• The more waves in the given space the higher the frequency

• http://brianleewhite.com/2012/01/14/understanding-sound-waves-frequency-and-amplitude-video/

• 0:55-1:19

Essential Questions

• Get with a partner and answer…

• What type of WAVE does light energy travel on?

How we See (Reflection)

• http://www.youtube.com/watch?v=iletCKDCt_0

Visible Light

• There is a small area in between Infrared waves & Ultraviolet waves that is important to us

• This we call VISIBLE LIGHT

• These are the only Electromagnetic waves that HUMANS can SEE

Visible Light

Visible Light

• Within the small area of visible light are photons

• These photons take on the color of that particular spot on the Electromagnetic Spectrum

Measuring Waves

• Visible Light is measured in Nanometers

• Each of the waves of visible color has a range of Nanometers

• They range from…– 380NM to 780NM

Visible Light• The waves

• The waves on the Electromagnetic Spectrum which we can see are– Red (380 NM)– Orange– Yellow– Green– Blue– Violet (780 NM)

Essential Questions

• Get with a partner and answer…

• What part of the Electromagnetic Spectrum is VISIBLE LIGHT?

Human Eye

• Humans can detect the waves/light between Infrared waves and Ultraviolet waves

• Humans have RETINAS that are sensitive to Electromagnetic waves between Infrared and Ultraviolet

Human Eye

• Inside the Retina are

① Rods② Cones

Rods• The human eye has about 100

million rods in its Retina

• The cones work with the rods to be miniature sensors of electromagnetic waves or light photons

• Rods are responsible for seeing black & white and is why our eyes “adjust to the dark”

Cones• The human eye has about 6-7

million cones in it’s Retina

• The cones work with the rods to be miniature sensors of electromagnetic waves or light photons

• Cones are what makes the eye see color. Rods are responsible for detecting– Red– Green– Blue

Relationships• Electromagnetic waves make up the

Electromagnetic Spectrum

• Within the Electromagnetic Spectrum between the Infrared & Ultraviolet waves is “Visible Light”

• Visible light shines down as white light. The white light hits an object and reflects a color

• The Rods & Cones inside our eyes are able to detect the visible light on the Electromagnetic Spectrum which is what enables us to see

Essential Questions

• Get with a partner and answer…

• What is the process of light being detected by the human eye?

Important Points• Electromagnetic waves make up

the Electromagnetic Spectrum

• Within the Electromagnetic Spectrum between the Infrared & Ultraviolet waves is “Visible Light”

• Within the Human eye is the Retina

• Inside the Retina are the Rods & Cones

• Rods help humans detect black & white light as well as see in the dark

• Cones let humans see color (rainbow) that is in between Infrared & Ultraviolet waves

• Photons are the particles of energy that move on an electromagnetic wave