Slide 1

Catalyst1. Whats the difference between kinetic and potential energy?Kinetic energy is moving. Potential energy is stationary but deals with height. They both deal with mass.

2. If you drop a bowling ball and a tennis ball from 5 feet, why will the bowling ball make a dent in the floor while the tennis ball wont? Dont they have the same potential energy?The bowling ball has more potential energy because its heavier.

3. Find the kinetic energy of a ball weighing 10 kg and traveling at 8 m/s. Ek = 0.5 * 10 * 82 = 320 J 11) Why are leaves green?

Why are leaves green?Leaves are green because they reflect green light and absorb red and blue light. Why do colors exist? Scientists use _______ to break light into a spectrum of colors.prisms

Why do colors exist?

ROYGBIV

The spectrum of visible light is called ROYGBIV: You can see ROYGBIV in a rainbow!edrangeellowreenluendigoioletDifferent colors of light have different ______________. Wavelengths are measured in ___________________ 1 billionth of a meter.

wavelengthsnanometers (nm)650 nm590 nm570 nm510 nm475 nm445 nm400 nmWhy do colors exist? The light you see is whats ___________ from an object. Black objects absorb all ______________. White objects reflect _________________. reflectedcolors of lightall colors of lightWhy do colors exist?

Leaves are ______ because they absorb all the _________________, which has more energy. They reflect the ___________, because it has very ____________. green red and blue lightgreen lightlittle energy

Why do colors exist? Red objects absorb everything but _________. Blue objects absorb everything but _________, etc.blue light red light

Why do colors exist?

1) A police officers blue suit: Blue light is reflected; everything else is absorbed.2) An astronauts orange suit Orange light is reflected; everything else is absorbed.3) A stop sign Red light is reflected from the sign, but all light is reflected from the word Stop4) A soccer ball All light is reflected from the white pentagons, and all light is absorbed into the black ones.

Absorption & Reflection (We do)5) Youre part of an interstellar exploratory mission. You land on one of the planets orbiting Alpha Centauri, the closest star to our solar system. Theres life on the planet but all the plants are blue! What can you assume about Alpha Centauri thats different than the Sun?

Electromagnetic WavesWave that can travel through empty space or matterConsists of changing electric and magnetic fieldsShortened to EMProduced by vibrations of electrically charged particlesElectromagnetic SpectrumDivided based on wavelength of the wavesRadio waves - longest EM wave the basis of all technology and communication devicesMicrowaves shorter than radio used in microwaves, radar, and communication with satellitesElectromagnetic SpectrumInfrared shorter than microwaves heat. Almost all things radiate heat. Used in infrared photography (for military intelligence)Visible Light very narrow range of the spectrumknown as ROY G BIV

Electromagnetic SpectrumUltraviolet produced by the sun shorter than visible causes sunburn, but kills bacteria!X-Rays very short wavelengths. X-Rays used in medical field cannot see thru lead (like SUPERMAN). Electromagnetic SpectrumGamma Rays shortest wave of all. Used in radiation treatment of cancerOver-exposure to either X-Rays or Gamma Rays is very detrimental to your health.

Absorption and ScatteringAbsorption when light passes through an object and the light is dimmer once it passes thruScattering interaction of light that causes light to change direction. Light scatters in all directions!What are you talking about???When light strikes an object, the light can be reflected, absorbed, or transmitted.Opaque: an object that absorbs all the light that strikes it most objects are opaque.AGAINTransparent: material that transmits light light passes thru like glassTranslucent: material that scatters light you cannot see thru like wax paper.ReflectionRegular reflection: when parallel rays bounce off a smooth surfaceDiffuse reflection: when parallel rays bounce off a bumpy surfaceMirrorsImage: a copy of an object formed by reflection or refractionPlane mirror: flat mirrorConcave mirrors or lenses: mirror curved inwardReal image: image is exactVirtual Image: image is distortedMirrors continuedConvex mirrors or lenses: Surface curves outwardPrinted/painted images are virtualRefractionWhen light enters an object and the direction is changed (like a fish tank)Index of Refraction: a measure of how much the light is bent.Prisms: 3-D piece of glass when light is caught all the colors of light are displayedLightRainbows: refracted light thru raindropsMirages: image of a distant object caused by refraction

COLORThe color of an object is the light it reflectsYou can change the image by changing the color of light and perhaps adding a filter.Primary colors of LIGHT: red, blue, green can be combined to make ANY colorOther colors are called secondary colorsColor continuedWhen the primary colors of light are combined in equal amounts they make white lightTechnically, there is no darkness (just like cold doesnt exist). So darkness, is simply the absence of light.PigmentsUsed to color other materialsOpaque substances that reflect colorVery different from lightAs pigments are added together, fewer colors of light are reflected and more are absorbed.So, what does that mean??The more pigment, the darker the color.Primary pigment colors are: cyan (blue), yellow, and magenta. Combine any 2 pigments in equal amounts and you get a secondary color.White is the absence of color.Black is the combination of all color.

The EyeTHE EYE!!!Made of the cornea, iris, pupil, lens, retina, nerves, etcThe cornea light enters here protects the eyeThe iris the colored portionThe pupil: looks black contracts and expands in lightMore on the Eye!Macula: yellow part of retina that gives us vision, without it youd be blindSclera: white, tough wall of the eye that serves to protect and give shape to the eyeVitreous Humor: jelly-like material that fills the eye provides shapeAqueous Humor: water-like material between cornea and lens that gives oxygen and nutrients to the eyeContinuedThe lens: convex lens that refracts lightThe retina: cells lining the eyeball - made of rods and conesRods: distinguish between black, white, and grayCones: see colorOne more timeThe optic nerve: sends signals to brain and turns the image right side up.Glasses (Lenses) : help to correct vision the eyeball is typically too long or too shortNearsightedness: can see close upFarsightedness: can see far away How do we use it?Telescopes: use lenses to reflect images from the skyMicroscopes: use lenses to magnifyCameras: uses lenses to focusLasers: Uses light and lenses to direct and intensify CDs, Surgery, Holograms, Optical fibers (phone lines), communication, and medicine