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.1.2 Explain 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?

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 (ZERO) 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

Electromagnetic Spectrum The Electromagnetic Spectrum is made up of 6 different kinds of Electromagnetic waves Radio Waves Microwaves Infrared Waves Ultraviolet Waves X-Ray Waves 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 Rods 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