Vocabulary •Ch. 10 •Ch. 12 • P. 290 (1-4) • P. 296 (1-7) • P. 303 (1-5) •Ch. 11 • P. 327 (1-6) • P. 354 (1-3) P. 360 (1-7) •Ch. 13 • P. 384 (1-5) Waves Notes Waves Notes • LINEAR MOTION= • HARMONIC motion from one point to another without repeating. – – – – Distance Time Speed Acceleration MOTION= motion that repeats over and over. HARMONIC MOTION • Cycle (cyclic motion) = a unit of motion that • repeats. Oscillator (oscillating system) = a system that shows harmonic motion. • clocks • solar system • Seasons • music & musical instruments • cell phones • fm radio • Period = time it takes for one cycle to occur. Frequency = the number of cycles per second. unit = Hertz (Hz) 1 Hertz = 1 cycle/second ex: human heartbeat = ½ to 2 beats per second ex: human voice = 100 to 2000 cycles per second Amplitude • a measure of how large the cycle is. • This is the energy of a wave. ex: waves = height of the wave sound = volume WAVES Transfer energy from place to place without transferring matter • a disturbance in a medium. • medium = matter that are able to carry a wave. – ex: air carries sound waves – water carries waves QUESTION: Can sound travel in space, in other words, could you hear in outer space? ANSWER: NO! Sound requires a medium to carry its energy. Since matter does not exist in space the sound energy would have nothing to travel on. Transverse Waves • = oscillations that are perpendicular (90º) to the direction the waves is moving. • oscillation^ wave motion > ex: water, light, S-waves in an earthquake Longitudinal (compression) Waves • = oscillations that are in the same directions as the motion of the waves. • oscillation> wave motion > • ex: sound, shock waves, P-waves -- earthquake NOTE CHECK TAKE 2 MINUTES: With a partner, check each other’s notes to be sure both filled in all blanks WAVES Can be: Can be: transverse compressional Matter moves: @ right angles to wave direction Matter moves: Along wave direction Wavelength is measured: Wavelength is measured: Crest to Crest Compression to Compression Examples: Examples: Wave on a rope Sound waves Waves on a lake Shock waves PROPERTIES OF WAVES WAVE TERMS • Frequency (f) = waves per second (measured in Hertz) – known as Pitch in sound & music • Amplitude = the height of the waves, the energy of the wave. – Measured from the resting position to the crest. • Wavelength (λ) = the length of one cycle. Distance from a point on a wave to the identical point on the next wave. Which of the graphs has an amplitude of 10 centimeters? 5 Name five parts of a wave: 1. __________________________________ 2. __________________________________ 3. __________________________________ 4. __________________________________ 5. __________________________________ 3 1 Compare and contrast the 2 types of waves: 1. Both = _______________________________ 2. Matter = ______________________________ 3. Matter = ______________________________ A wave is = 1. _____________________________________ WAVE SPEED • Speed = the velocity the wave is traveling. • velocity = wavelength x frequency • v=λx f • units f = Hertz (Hz) λ = meters (m) v = meters/second (m/s) Ex: An ocean wave has a frequency of 2 Hz and a speed of 20 m/sec. What is the wavelength of this wave? λ = v/f λ = 20 m/s ÷ 2 Hz = 10 m Examples of the Speed of Waves • Speed of Light 300,000,000 m/s 300,000 km/s 186,000 miles/s NOTE CHECK TAKE 2 MINUTES: With a partner, check each other’s notes to be sure both filled in all blanks Examples of the Speed of Waves • Speed of Sound • Calculate the Speed – Approx 340 m/s – Approx 770 miles/hr – This will vary a great deal due to temperature and atmospheric pressure of Sound WAVES INTERACTIONS what results from waves hitting objects • Reflection = The wave can bounce off and go in a new direction. • Angle of Incidence = inbound angle • Angle of Reflection = outbound angle • measured from the perpendicular and both angles are EQUAL Which is the angle of incidence? Which is the angle of reflection? Refraction = The wave can pass straight into and through the obstacle and are bent due to the change in density of the medium. Diffraction = The wave can bend around or through holes in the obstacle. Absorption = The wave can be absorbed and disappear. NOTE CHECK TAKE 2 MINUTES: With a partner, check each other’s notes to be sure both filled in all blanks WAVE INTERFERENCE • when 2 or more waves meet. • Constructive Interference = When waves meet “in phase” trough to trough or crest to crest. The resulting waves become larger. • ex: Sound = resonance Resonating Chambers = sinuses, guitar, musical instruments Wind Tacoma Narrows Bridge collapse in the 1940s Tacoma Narrows Bridge “in phase” WAVE INTERFERENCE • Destructive Interference = When waves meet “out of phase” crest to trough. The resulting waves become smaller or even cancel each other. • ex: Dissonance = sound waves meet out of phase and noise results. “out of phase” THE DOPPLER EFFECT • radar speed detectors • metrology to detect wind speeds & on coming weather fronts • very noticeable in auto racing • Approaching Object = sound wave are • compressed due to the speed of the approaching object thus increasing the frequency or pitch of the sound of the object. Departing Object = sound waves are stretched because the object is moving away from the listener thus decreasing the frequency or pitch of the sound of the object. NOTE CHECK TAKE 2 MINUTES: With a partner, check each other’s notes to be sure both filled in all blanks THE ELECTROMAGNETIC SPECTRUM • Electrons = the negatively charged particle in the atom is involved in light. – Electrons can absorb energy by various ways causing them to jump to a higher energy level(s). – Then they give off energy in the form of light when they move from the higher to lower energy level(s). Parts of the electromagnetic spectrum • Radio waves • Microwaves • Infrared • Visible Light Longest Wavelength Lowest Frequency – ROY G BIV • Ultraviolet • X-rays • Gamma rays Short Wavelength Highest Frequency THE ELECTROMAGNETIC SPECTRUM • Radiowaves (1 km to 30 cm) – ex: AM & FM radio, TV signals • Microwaves (30 cm to 1 mm) – ex: microwave ovens, cellular communication • Infrared (1 mm to 70 nm) – ex: heat, sensors, guidance systems • Visible Light (70 nm - 400 nm) – ex: ROY G BIV • Ultraviolet – ex: sunburns, harmful to eyes, disinfect by killing bacteria • X-Rays – ex: medical & dental uses, inspect metal welding • Gamma Rays – ex: originate from the sun, atomic radiation ROY G BIV • Red • Orange • Yellow • Green • Blue • Indigo • Violet Longest wavelength Shortest wavelength Lowest frequency Highest frequency Visible Light • Optics = the study of light • Lasers = a single frequency of light COLOR • Primary Colors of Light the color of transmitted light you see. The light source –Red –Green –Blue • Red + Green + Blue = White COLOR Primary Colors of Pigment A pigment is a colored material that is used to change the color of other substances. Reflected light color –Magenta –Yellow –Cyan • Magenta + Yellow + Cyan = Black Computer Settings • pixel = dot = 3 numbers to assign the color (0-256) • Red, Green, Blue = RGB – ex: (0, 0, 0) = black • 256 x 256 x 256 = 16,777,216 *possible different colors The Eye • Lens = Tiny muscles around the eye change the • • shape of the eye to focus the image when light passes through. Iris = The colored part of the eye that controls the amount of light entering the eye. Retina = A membrane lining the inside of the back of the eye composed of light sensitive receptors that are stimulated by the different wavelengths of light that makeup the image. The Retina • Rods = Rod-shaped receptors involved in night vision, peripheral vision (corners of the eyes) and making out the outline of objects. • Cones = Cone-shaped receptors that contain color-sensitive pigments to detect red, blue, green and all their combinations. Optical Illusion • seen images that “trick” the brain into observing something that is not real. Mirage • A false image in the distance produced by the refraction of light through air layers of different densities. Ex. The appearance of water in the distance Mirage SOUND • a pattern of air oscillations consisting of areas of high pressure to low pressure. Sound consists of longitudinal (compression) wave thus it is impossible for sound to travel in space. • Acoustics = the science or study of sound • Amplitude = Loudness or Volume measured in Decibels (dB) Decibels (dB) • 10 – 15 dB • 65 dB • 70 dB • 90 dB • 120 dB whisper (3 ft away) normal conversation (3 ft away) city traffic jackhammer (10 ft away) threshold of physical pain • 90 dB is 2x louder than 70 dB Frequency (Pitch) – 20 Hz – 100 Hz – 500 Hz – 5000 Hz – 10,000 Hz – 20,000 Hz thunder bass guitar average male voice highest note on a piano jet turbine engine highest human limits • human range 20 to 20,000 hertz (best 100 to 2000) *test ??? Speed of Sound • approx. 340 m/s or 770 mi/hr (in air) • Calculate • speed varies greatly based on the density of the medium • ex: in air factors include altitude, humidity and temperature Supersonic • super = above • sonic = sound • motion that is faster than the speed of sound. Ultrasound • Medical use of sound waves to give internal images of the human body. • Sonogram = Images of the baby during pregnancy.