2Mechanical Wave Mechanical waves require a medium Examples: shaking a rope or string, ocean tides, slinky and spring, diffusion of heat, etc.Waves carry energy from one location to another
3Types of Mechanical Waves Three typesTransverse WavesLongitudinal WavesSurface Waves
4Transverse WavesParticles vibrate perpendicular of the direction the wave travels.Trough is the lowest point and crest is the highest point.Examples: A shaken string; electromagnetic radiation, radio waves, cell phone signals; AC current; etc.
5Longitudinal Waves Particles vibrate in the direction of propagation! Experiences compression: the area where the particles are most close together and rarefaction: the area where the particles are most distance from one another.Examples: Sound waves, can be made on slinky, air cannons, etc.
6Surface WavesA surface wave travels along a surface that separates two medium.
7Wave PropertiesPeriod (T) – The time required to complete one cycle for a wave. Units are in seconds.Frequency (f) – The number of complete cycles in a give time. Units of f are in Hertz (Hz). AKA inverse seconds 1/sThis means T=1/f and f=1/T
8Wave Length!Wavelength (λ) is the distance between crest or toughs for transverse waves and the distance between compressions or rarefactions for longitudinal.Lambda is how your pronounce λWave length units are meters
9Wave Speed!!!!!!Wave speed is equal to wave length times frequency that is V= λ x for if you hate λ wave speed = frequency x wave lengthWave speed has units of meters per second (m/s)The speed of light is always c however!
10AmplitudeThis is how “big” the wave is or rather how large the displacement of the wave is from the origin.
11Behavior of waves So very many properties. Reflection, Refraction, diffraction, interference, standing waves
12ReflectionReflection occurs when a wave bounces off a surface/barrier it is on able to pass through.The speed and frequency of the wave does not change during a reflection.
13RefractionRefraction occurs when the wave enters a new medium at an angle and changes direction.Wave speed does change upon entering a new mediumThis is how rainbows are created and how ocean waves change direction.
14DiffractionDiffraction is the bending of a wave through or around an obstacle.This is an important property of light and is often used in quantum mechanics.
15Interference!!!!!!!!!!!oneone1!!11!This is an extremely important property of waves!There are two types: constructive and destructiveConstructive and destructive interference are both examples of the superposition.Superposition is how sound canceling headphones work, amplifiers, musical instruments (via the formation of standing wavesThere is no music without superposition!
16Constructive Interference Two like waves combine to have there amplitudes add forming an over all larger amplitude wave.For sound, this makes the sound louder!
17Destructive Interference Two waves combine to make a smaller amplitude wave.This makes sound more quite and is how sound canceling head phones work!
18Standing WaveStanding waves only form if multiple half of wavelengths fit into the length of a vibrating cord or string.They have nodes and antinodesNodes are at a location of zero displacementAntinodes are at the highest points of the wave
19Sound waves Sound, is again, a longitudinal wave! Sound travels at about 343 m/s at room temperature
20Decibels The louder a sound is the higher its intensity Larger intensities mean higher decibelsA rock concert is often at the threshold of pain and you will lose hearing with out protection
21Pitch and FrequencyA pitch is the frequency of sound as you perceive it.High frequencies yield a high pitch and low frequencies a low pitchMiddle C has a frequency of 261 Hz, while an F# has a frequency of about 370 Hz. Well for first harmonics anyways.
22Doopppplllllleeeeeeerrrrrrrrrrrrrr The Doppler effect is the change in frequency of a sound caused by the motion of the listener and/or source.This effect also affects light from distance stars and is known as red/blue shifted light.
23Electromagnetic Waves! AKA light and much more!Electromagnetic waves are created from accelerating electrons.Electromagnetic waves can travel through a vacuum and matter. This means an electromagnetic wave require no medium to travel!
24Electromagnetic Wave Speed All electromagnetic waves travel at c, the speed of light in a vacuum.Also, Electromagnetic is often abbreviated as EM.
25EM frequencyElectromagnetic waves can vary in wavelength and frequencyAgain v = f x λHowever, v = c for EM waves unless otherwise stated.
26EM Waves BehaviorEM waves behave very peculiar, they behave both like waves and particles.This is known as wave particle duality and was discovered by Albert Einstein during his studying of the photoelectric effect.EM energy is carried by little particles called photons and a photons energy is dependent on a waves frequency.
27Wave Spectrum!!!EM waves come in all sorts of variety and are not just limited to visible light.
28Radio WavesIncludes both FM (frequency modulated) and AM (amplitude modulated) wavelengthAlso includes: TV’s
29Microwaves Includes microwaves (hopefully obviously) Microwaves work by hitting the dipole moments in fats and water stored in food producing thermal energyAlso includes: radar
30Infrared WavesInfrared is the wave length of light are bodies give off and most objects produce.Infrared light is also used in TV remotesSome infrared light can be seen by your cell phones camera!
31Visible LightThis is the ROY G. BIV we see from a rainbow and is the light we can see.
32Ultraviolet WavesThis is the invisible light produced by the sun responsible for sun burns!It can kill a large amount of germs and bacteria and is often used for medical sterilization
33X-Rays X rays have very short wave lengths and have a high energy They can penetrate a large amount of matter and are often used in medical applications
34Gamma Rays The highest frequency waves possible. These waves can slice through cell membranes and damage your DNA possibly causing cancerIt is also used to treat cancer however, by destroying the cancer cells!