5*2 Making Waves WDYS??? (p492) . WDYT??? To make a wave, water _____.

5*2 Notes: DEMOSTRATION #1 Part A: “Stadium Wave” The wave moved _____. The students moved _____. The wave’s particles move _____, causing the wave to move _____. One can change the 1)_____ 2)_____ and 3)_____.

5*2 Mini-Lab Part A: Amplitude v. Velocity QUESTION: Does amplitude (size of the wave) of a wave affect the velocity? Sketch it!!! (independent/dependent variable) Hypothesis: If the amplitude increases, then the velocity _________________________.

DATA: AMPLITUDE v. SPEED DATA Amplitude 10.0 20.0 30.0 Trial 1 time   DATA Amplitude 10.0 20.0 30.0 Trial 1 time Trial 2 time Trial 3 time Avg.time (s) Distance (m 2 Avg. Speed Class Data

ANALYSIS: Sketch it!!! Sketch your data on a line graph…. How do the speeds of the waves compare for the 3 different amplitudes of the 2.0 meter distance? (be clear if one is faster or not)   Did amplitude influence the speed of the waves for the 2.0 meter distance? Explain CONCLUSION: If the amplitude _________, then _____________________.

5*2 Demo #2 2. TAPE the middle of the coil spring b) The motion of the piece of tape is __________; aka __________ because it moves at RIGHT ANGLES. d) AMPLITUDE  HEIGHT of the wave from CREST to TROUGH  Labeling a wave

5*2 NOTES: WAVES Waves are: A transfer of ENERGY with NO transfer of mass DISTURBANCES that travel through a medium Medium  a solid (Earth), liquid (water), and/or gas (air) through which a wave travels

Waves are DIRECTLY related to the transfer of energy from one location to another EXAMPLE the larger the amplitude, the larger the energy transfer, the louder the sound, the brighter the light

TRANSVERSE WAVES TRANSVERSE WAVES  motion of the wave is PERPENDICULAR (at RIGHT angles) to the direction in which the wave is traveling ***MORE energy, LARGER amplitude*** ***LESS energy, SMALLER amplitude***

Wavelength (λ)  crest-to-crest OR trough-to-trough Frequency (f)  number of times the wave moves UP&DOWN /second Hertz (Hz)  the unit of frequency (f ) Humans can hear very low frequencies (20Hz) to very high (20,000Hz) Period (T)  time for ONE WAVE (crest & trough)to pass Period (T) and Frequency (f) are INVERSELY related They go in OPPOSITE directions: T = 1/f f = 1/T

λ = v / f f = v / λ v = f × λ VELOCITY OF A WAVE: If you are given a distance and time, calculate it the “old fashioned” way or…. If you are given frequency, wavelength and/or velocity---THE NEW WAY!!! Wavelength (λ) Frequency ( f ) Wave Speed (v) λ = v / f (m) f = v / λ (Hz) v = f × λ (m/s)

Characterized by wave speed (v) to where the speed depends on the medium’s consistency The distance the wave crest moves is 2m in 0.2s, what is the wave speed??? What is the wave speed with a frequency of 4Hz, a wavelength of 0.75m, and an amplitude of 1.5m???

LONGITUDINAL WAVES 2. LONGITUDINAL WAVES  motion of the wave is PARALLEL to the direction in which the wave is traveling; aka COMPRESSIONAL Wave Speed = distance traveled = v time elapsed t

5*2 DEMO #3 Part C: LONGITUDINAL WAVES on a Spring 1. Student #1 = Just holds the SLINKY against the floor Student #2 = make a wave The SLINKY moves ________ as the wave moves _______________along the spring. Draw AND Label the wave motion:

STANDING WAVES 3. STANDING WAVES are wave patterns that do NOT move through the medium Node  spot in a standing wave where wave is completely stationary (still/not moving) Antinode  spot in a standing wave where wave has its largest displacement

WAVE INTERFERENCE Wave interference: when 2(or more) wave INTERACT with each other: Destructive Constructive

5*2 Demo #4 3-5.What happens when BOTH students make a wave on the coil spring ??? When two waves are made in the SAME direction, the wave amplitude’s are __________ and therefore _____. “Constructive” When two waves are made in the OPPOSITE direction, the wave amplitude’s are __________ and therefore _____. “Destructive”

5*2 Checking Up (p502) Write questions!! #1-3 5-2 PTG (505), # 1-13, (skip 9)

5*2 Physics To Go (p505) Define and give the Units for the following terms: Amplitude = Wavelength (λ) = Frequency (f) = Speed (v) = By making the slinky move FASTER, the amplitude and wavelength _____ while the frequency _____. I can measure the wavelength by _____. I can measure the frequency by _____.

5*2 Physics To Go (p505) 5. The equation for wave speed = _____. 6. A standing wave is _____. Drawing : 7. Transverse waves are _____ while compressional waves are _____. Draw AND label each wave: 8. To change the frequency, I would shake the slinky _____.

5*2 Physics To Go (p505) 10. Draw the picture described in the question: a) λ = b) f = 1 / T = c) v = λ × f = 11. Draw the picture described in the question: a) The pulses ADD UP because they are on the SAME side, therefore the amplitude is _____. b)The pulses SUBTRACT because they are on OPPOSITE sides, therefore the amplitude is _____.

5*2 Physics To Go (p505) 12. v = λ × f = v = d / t = 13. Draw the picture described in the question: The clothes are located at the _____. λ =

5*2 TOTD