2 Waves rhythmic disturbances which transmit energy through a medium [substance – solid, liquid, or gas]ex: light & sound [note: sound and other types of waves can carry information in the form of energy]
3 WavesCord Demo – does the cord itself move from place to place? is it traveling with the wave?Waves move through the medium – they do not move the medium itself.like the wave at a sporting event
4 Types of Waves Mechanical waves – need to travel through matter transverse wavescompressional [aka longitudinal]Water waves move in a combination of these movements
5 Transverse Waves Transverse waves matter in medium moves back and forth at right angles to the wave’s energyElectromagnetic rays travel in transverse wavesif wave is traveling L or R, the movement of the medium is up and down.if wave is traveling up or down, the movement of the medium is L & R
6 Transverse Waves Parts of a Transverse Wave draw this wave on your paper in the space provided.
7 Transverse Waves Parts of a Transverse Wave crest the highest point of the wave – highest Ethere can be many crests
8 Transverse Waves Parts of a Transverse Wave trough the lowest point of the wave – lowest Ethere can be many troughs
9 Transverse Waves Parts of a Transverse Wave resting position does not have to be at zero!
10 Transverse Waves Parts of a Transverse Wave amplitude the furthest distance from the resting positionfrom resting position to either crest or trough
11 Transverse Waves Parts of a Transverse Wave wavelength distance of one wavedistance between two equal points on a wave
13 Longitudinal Waves Longitudinal Wave [aka Compressional Wave] matter in the medium moves back and forth along the same direction of the wavesound and seismic wavesimagine a coil: a slinky or springcompress coils then release, wave moves coils in a compression to other side
14 Longitudinal Waves Parts of a Longitudinal Wave Draw a coil on your sheet like the one below, with areas of densely bound coils, and areas of lesser bound coils
15 Longitudinal Waves Parts of a Longitudinal Wave rarefaction a non-compressed area of this type of wavepoint of lowest energy
16 Longitudinal Waves Parts of a Longitudinal Wave compression a compressed area of this type of wavepoint of highest energy
17 Longitudinal Waves Parts of a Longitudinal Wave wavelength distance of one wavedistance between two equal points on a wave
20 PracticeWhat is a wave?What is the name for the material through which a wave travels?In which kind of wave do the particles of the medium vibrate in the same direction as the wave?What is transmitted by a wave?In which kind of wave do the particles of the medium vibrate at right angles to the wave?How is a crest similar to a compression / a trough similar to a rarefaction?
21 Wave MeasurementsFrequency – number of waves that pass a certain point per unit of time. [waves per time]measured in Hertz [Hz] for waves per secondas waves travel faster [higher frequency], the wavelength decreaseswhat type of relationship is this?1 Hz = 1 wave per second
22 Wave MeasurementsPeriod = time it takes to complete one cycle [time per wave]T = t / # of wavesORthis is the inverse of frequencyT = 1/ f
23 PracticeThe period of a wave is 3 seconds. What is its frequency?
24 Wave Measurements Wave Speed can depend on the medium sound travels best through solids [particles close together] but radio waves and others can’t travel through them
25 Wave Measurements Calculating Wave Speed recall: speed = distance / timerecall: frequency = waves/timewave speed = wavelength * frequencyv = λ * fdoes this make sense? let’s seewave speed (m/s) = wavelength (m) * waves (#) time (s)
26 Electromagnetic Waves Electromagnetic Waves – do not need matter to transfer energywave transferred by vibration of magnetic & electric fieldsEMS = range of electromagnetic radiationEMS contains Visible Light in roughly the center of spectrum R O Y G B I V
27 Electromagnetic Waves all EM waves travel at the speed of light roughly 3 x 108 m/s or 186,282.6 miles per secondvariable for speed of light = Cthis is currently the fastest speed in the universe