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EMS/EMR Waves. Electromagnetic Wave Simulations of Science!. Labels for Wave Models of Science!. The Electromagnetic Spectrum & Light. _______. _______. _______. _______. _______. _______. _______. _______. _______. _______. Electromagnetic Spectrum/Radiation.
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Electromagnetic Spectrum/Radiation • Electromagnetic waves: are transverse waves produced by the motion of electrically charged particles. • They DO NOT need a medium! • Can travel though empty space at 300,000km/s or 186,000 miles/sec • Radiation: The transfer of energy by electromagnetic waves. • Abbreviations… • EMS = Electromagnetic Spectrum • EMR = Electromagnetic Radiation
Mnemonics to Remember Spectrum Order… From smallest (gamma) to greatest (radio)… • Great, X-Men Uses Very Important Strategy: Running • Greg's X-Ray Unveiled Viral Intestinal Sores Rotting From greatest (radio) to smallest (gamma) … • Reading Music Is Very Unsatisfactory forXylophones and Glockenspiels • Really Mrs. neri Is Very, Ultimately, Xtra Great
Electromagnetic SpectrumElectromagnetic waves that are classified in ascending order of energy (frequency); they propagate at the speed of light (300,000 km/s). visible light • Electromagnetic radiation that is perceived by the human eye and ranges from red to violet. gamma rays • Electromagnetic waves of very high frequency that are emitted by radioactive bodies; they are the most radiant and harmful rays and are used especially in treating cancer. X-rays • Electromagnetic waves used especially in radiology; frequent exposure can be harmful. ultraviolet radiation • Electromagnetic waves used especially to tan skin and in microscopy, medicine and lighting (fluorescent tubes). infrared radiation • Electromagnetic waves emitted by warm objects; their many uses include heating, medicine, aerial photography and weaponry. microwaves • Short electromagnetic waves; their many applications include radar detection and microwave ovens. radio waves • Very long electromagnetic waves (about 1 meter) having low frequency; they are used to transmit information (television, radio)
Put in your notes above or below your picture… Long Wavelength Short Wavelength Low Frequency High Frequency Low Energy High Energy
Radio: Yes, this is the same kind of energy that radio stations emit into the air for your boom box to capture and turn into your favorite Mozart, Madonna, or Justin Timberlake tunes. But radio waves are also emitted by other things ... such as stars and gases in space. You may not be able to dance to what these objects emit, but you can use it to learn what they are made of. • Microwaves: They will cook your popcorn in just a few minutes! Microwaves in space are used by astronomers to learn about the structure of nearby galaxies, and our own Milky Way! • Infrared: Our skin emits infrared light, which is why we can be seen in the dark by someone using night vision goggles. In space, IR light maps the dust between stars. • Visible: Yes, this is the part that our eyes see. Visible radiation is emitted by everything from fireflies to light bulbs to stars ... also by fast-moving particles hitting other particles. • Ultraviolet: We know that the Sun is a source of ultraviolet (or UV) radiation, because it is the UV rays that cause our skin to burn! Stars and other "hot" objects in space emit UV radiation. • X-rays: Your doctor uses them to look at your bones and your dentist to look at your teeth. Hot gases in the Universe also emit X-rays . • Gamma-rays: Radioactive materials (some natural and others made by man in things like nuclear power plants) can emit gamma-rays. Big particle accelerators that scientists use to help them understand what matter is made of can sometimes generate gamma-rays. But the biggest gamma-ray generator of all is the Universe! It makes gamma radiation in all kinds of ways.
Radio Waves • All around us • Long wavelengths and low frequencies. • Radio, TV, cellular phones, cordless phones, etc.
Microwaves • Radio waves with the highest frequency and energy. • Communications and microwave ovens!
Infrared Radiation • Slightly lower frequency than visible light. • Felt as heat • Infrared lamps keep your french fries warm! • Used in Remote Controls
IR does not penetrate walls and so does not interfere with other devices in adjoining rooms. Infrared is the most common way for remote controls to command appliances.
Visible Radiation • Or light, is the only part of the electromagnetic spectrum you can see! • Each different wavelength of light has a different color!!
Ultraviolet Radiation • Higher frequency than visible light. • Greater penetrating power! • Helps skin cells produce vitamin D, which is needed for healthy bones and teeth! • Sterilize surgical instruments • Over exposure kills healthy cells!!! • Sagging, dry skin, skin cancer! • Sunblock and sunglasses!!!
X Rays • X rays have a shorter wavelength and a higher frequency than ultraviolet radiation. • Higher energy allows X rays to travel through some types of matter such as your skin and muscles.
Gamma Rays • Have the highest frequency and are the most penetrating of electromagnetic waves! • They are emitted from the nuclei of radioactive atoms. • Earth receives some from space. • Can be used to kill cancer cells.
Types of Reflection • Reflected light is when light is not completely absorbed by an object. • The type of surface affects the type of reflection. • Regular/Specular reflection- smooth surface, forms a clear image. (flat mirror) • Diffuse reflection- rough surface, forms a fuzzy image.
Ex) Mirror Ex) Road
Refraction • The bending of light
Light Reflection & Refraction Reflection Refraction Ex) Mirror Ex) Road White Light ROYGBIV Colors of the Rainbow!
Diffraction Diffraction= Bending and spreading of waves usually around an obstacle
Mirrors Convex mirrors- a mirror with a surface that curves outward Images appear smaller & farther away “objects are closer than they appear” Concave mirrors- mirror with a surface curved inward. Form either virtual images or real images depending on the position of the object
What do cameras, telescopes, microscopes, and movie projectors have in common? They all use lenses to create images!
Lens • A transparent object (see through) that refracts (bends) light waves such that they converge or diverge to create an image • Lenses are classified by shape • There are 2 types • Convex • Concave
Concave Lens • Lens is thinner in the middle than at the edges • Does not produce a real image • Produces a Virtual Image • Smaller than objects • Uses Telescopes, Microscopes, and Nearsighted Eyeglasses
Convex Lens • Lens is thicker in the middle than at the edges • Produces a real image • Light Rays Refract Toward Each Other • A real image is larger than the object • Side Mirror on car “Objects appear smaller than they actually are” • Uses= Magnifying Lenses, Cameras, and Farsighted Eyeglasses
Near Sighted • Can see near but not far because light is focused in front of the Retina • Concave Lens (Curves Inward & Thin in Middle) • Light Diverges or Spreads out back towards the Retina
Far Sighted • Can see far but not near because light is focused behind the Retina • Convex Lens (Curves Outward & Thick in Middle) • Light Converges or Comes Together more in front of Retina
Convex vs. Concave • Convex Mirror= Curved Outward Like the Back of a Spoon! • Concave Mirror= Curved Inward Like the Inside of a Spoon! • Convex Lenses = Curve Outward, Thick in the Middle, & used for Farsightedness! • Concave Lenses = Curve Inward, Thin in the Middle, & used for Nearsightedness! (Near a Cave!) • http://mail.colonial.net/~hkaiter/electromagspectrum.html
Concave vs. Convex Concave Mirror Concave Lens Convex Mirror Convex Lens
