P199: Introduction & Start of Sound. Lecturer Stacy McCormack Physics Department, Indiana University. VIBRATION. Topic 1: Sound. MISCONCEPTION!. Molecules in solid, liquid, gas. Sound in space?.
Lecturer Stacy McCormack
Physics Department, Indiana University
Molecules in solid, liquid, gasSound in space?
Longitudinal wave-individual vibrating objects move right or left and the disturbance also moves right or left (ex. sound wave)
Transverse wave-individual objects move up and down, but disturbance moves right or left (ex. water wave)
Amplitude-height from rest position (determined by the amount of energy), loudness
Wavelength-distance between two like molecules (humans hear from 0.65 in to 54 ft, musical note A is 31 in)Sound Waves & Terms
Node-a place where there is NO VIBRATION-the molecule always remains in the same location
Antinode-a place where there is MAXIMUM VIBRATION-the molecule is movingWhy are some sounds high-pitched and others low-pitched?
NOTE: Distance between adjacent node and antinode is ¼ wavelength
small frequency=low pitch
Small or short distance between node and antinode=
large frequency=high pitchTuning fork
Antinode: MAXIMUM VIBRATION
Node: NO VIBRATION
Small distance between node and antinode
NPitch and Tuning Forks
Remember: distance between node and antinode is ¼ wavelength
So to find wavelength, take N-A distance and multiply by 4!
Creates an antinode
Closing off one end makes a node
Makes wavelength longer than if just left open
ADemonstration with two twists