DO STOP WORK Finish Begin collecting lab data

DO STOP WORK

� Finish � Begin collecting lab data. to explain the observations you made during the lab.

� Physics � SLC Club today Thursday � Answer Sheets � Missing Polarization Lens

� Let’s � Go finish collecting our lab data. to your last station.

Take out your “What is light” lab

$� Emission � Transmission � Reflecting/Scattering � Absorption � Dispersion � Polarization � Diffraction$

� Emission � Transmission � Reflecting/Scattering � Absorption � Dispersion � Polarization � Diffraction

�A light bulb emits visible light; the energy of the light comes from electrical potential energy supplied to the light bulb.

� Some forms of matter, such as glass or air, transmit light, which means allowing it to pass through.

� Light can bounce off matter leading to what we call reflection (when the bouncing is all in the same general direction) or scattering (when the bouncing is more random).

� When you place your hand near an incandescent light bulb, your hand absorbs some of the light, and this absorbed energy warms your hand. These bananas absorb all colors of light except yellow. Instead yellow is scattered, so the bananas appear yellow!

� What is emission? � What is transmission? � What is reflecting/scattering? � What is absorption?

� When white light travels through a prism it disperses into a rainbow, showing that white light is made up of all the color we can see.

� When light passes through a polarizing filter it is only allowed to vibrate in one direction. � Light cannot pass through two polarizing filters that are set 90 degrees from one another.

$� When a wave encounters an obstacle, or a slit is diffracts and a$

� When a wave encounters an obstacle, or a slit is diffracts and a pattern is produced on a screen.

$� What is dispersion? � What is polarization? � What is diffraction?$

� What is dispersion? � What is polarization? � What is diffraction?

� Jump to “Details of light properties” Power. Point

� How does light behave like a particle? � How does light behave like a wave?

� Wave-Particle Duality says that light exhibits both wave and particle properties. This duality addresses the inability of classical concepts like “particle” and “wave” to fully describe the behavior of light. � This is a central concept in quantum mechanics.

�A photon is one particle of light that obeys the wave-particle duality of light.

� Wave-particle duality � Photons always want to travel at the speed of light in a vacuum: � Every photon has a specific frequency and wavelength that obey the equation: � f is the frequency of the photon (Hz) � Lambda is the wavelength of the photon (m)

� Photons have energy that obey the equation: �h is Planck’s constant: �E is the energy measured in Joules (J) � Note: Not every photon has the same energy

� Explain Heisenberg’s uncertainty principle. DO STOP WORK

� Solve for the velocity, wavelength, frequency, energy, and type of light.

� Remember your long answers are due tomorrow. �I’ll be collecting them so write your answers in the question packet too. � Does anyone have the completed letter slip?

� For a photon that has wavelength of 650 nm find its velocity, frequency, energy, and color. � Velocity: �The velocity of a photon is always the same in a vacuum.

� Frequency of the photon:

� Energy � Or: of the photon:

� Color of the photon � RED!

� Which has a larger wavelength, red or blue light? � Red � Which has a greater frequency, red or blue light? � Blue � Which � Blue has more energy, red of blue light?

� What color light has a wavelength of 200 nm?

� Gamma Rays, X-Rays, Ultraviolet, Visible, Infrared, Microwaves, and Radio Waves are all part of the electromagnetic spectrum. � They are all electromagnetic rays � We can only detect visible electromagnetic waves with our eyes, but this doesn’t mean the visible waves are a different type of wave than the ones we can’t see.

� How can chicken wings be used as an analogy for the electromagnetic spectrum? � Spicy Cajun Style � Spicy Glazed � Baked Buffalo � Sesame � Maple � Broiled Barbecued � Inferno � Plain

� TV, FM, AM, Wifi, cell phones � Wavelength – Football field to a baseball � Can you hear radio waves? � “Most people associate the term radio with sound, but radio waves are a form of light with long wavelengthtoo long for our eyes to see. Radio stations encode sounds as electrical signals and broadcast the signals as radio waves. What we call “a radio” in daily life is an electronic device that receives these radio waves and decodes them to re-create the sounds played at the radio stations. ”-The Cosmic Perspective

� Microwaves �Microwave oven, Radar �Wavelength – Lacrosse ball to a small dot � Infrared �People, light bulbs �Wavelength – Cell to bacteria

� Visible �The only electromagnetic waves we can see �Wavelength – 780 nm to 380 nm � Ultraviolet �The cause of sunburn �Wavelength – Virus to a protein

X-Ray machines � Wavelength – Protein to a water molecule � What could you see with X-ray vision? � � “The “X-rays” that the doctor or dentist holds up are not a form of light; they are just pieces of film. The images of your bones and teeth are made with the help of a special machine that works somewhat like the flash on an ordinary camera but emits x rays instead of visible light. This machine flashes the x rays instead of visible light, and the x rays that are transmitted through your body are recorded on film. Thus, what you see is the image left by these x rays, not the x rays themselves” The Cosmic Perspective

Radioactive elements � Wavelength – Water molecule to even smaller � Is all radiation dangerous? � � Many people associate the word radiation with danger. However, the word radiate simply means “to spread out from a center” (radius-radiation). Radiation is energy being transmitted through space. � High-energy forms of radiation, such as particles from radioactive materials or x rays, are dangerous because they can penetrate body tissues and cause cell damage. Low energy forms of radiation, such as radio waves, are usually harmless.