How do you describe a wave? I. Properties of a Wave A. Amplitude 1. Height of a wave from the midline 2. Greater amplitude Greater Energy
Bright Bulb = High Amplitude Dim Bulb = Low Amplitude Bright Bulb = High Amplitude
Quiet = Low Amplitude Loud = High Amplitude
Little Waves Big Waves Small Amplitude Large Amplitude Little Energy Great Energy
a. ex. crest to crest, trough to trough 2. Also called one “cycle” B. Wavelength (λ) 1. Distance between two equal points of a wave a. ex. crest to crest, trough to trough 2. Also called one “cycle” C. Period (T) 1. The time it takes to complete one cycle A A B B a. Usually measured in seconds
D. Frequency (ƒ) 1. The number of waves that occur each second a. “cycles per second” b. Measured in a unit called Hertz (Hz) 2. Faster vibration higher frequency 3. Frequency and Period are “inverse” frequency = 1 . 1 period b. period = 1 . 1 frequency
What is an “Inverse Proportion?” Frequency Period Period Frequency
Todays Lab: Frequency & Period Problem 1: Find the frequency of a pendulum for FIVE different lengths and graph it. Problem 2: Using the same data you just collected, graph the period of the wave vs length. Problem 3: Explain, in one sentence each, what the graphs mean.
# of Swings in 10-sec. Frequency (Hz) Period of the wave (s) Length (cm) # of Swings in 10-sec. Frequency (Hz) Period of the wave (s) Average Average Average Average Average
What you will be graphing... Graph #1: Length vs Frequency Frequency (Hz) Length (cm) Graph #2: Length vs Period Period (s) Length (cm)