Wednesday, January 30, 2008

Wednesday January 30th

Today we talked more about waves! There are 5 characteristics of periodic waves they are:
Frequency

Period
Amplitude
Phase
Wavelength
Speed
Wave Front



Frequency


Frequency is the number of vibrations per unit of time. The SI Unit of time is hertz (Hz) and symbol for frequency is “f.” 1 Hz= 1 s^-1. This picture shows different frequency waves.




Period

Period is the time required for one complete vibration. The symbol for Period is “T” the SI Unit is second and it is the reciprocal of frequency T=1/f



This shows one period of a graph.






Amplitude


Amplitude is the maximum Displacement of a particle of the medium from its rest position. Another name for amplitude is height (of the wave).
Examples:



  • Light wave amplitude

  • Brightness

  • Sound wave

  • Amplitude

  • Loudness



Phase
Waves that cross paths while traveling in the same direction are considered to be in phase
Phases have
o The same displacement from the rest position
o The same direction of motion




Here wave 1 and wave 2 are said to have a phase difference of 2(pi), or simply are in phase, because both waves have the same wavelength and rise and fall together. Any two waves with a phase difference of a multiple of 2(pi) are in phase.



Wavelength



  • The wavelength of a wave is the distance between any two adjacent corresponding locations on the wave

  • The distance is usually measured in one of three waves

  • Trough to trough

  • From the start of a wave cycle to the next starting point

  • Crest to next crest

  • Shown below:


Speed of a Wave

  • The speed of a wave equals the product of wavelength and frequency

  • Examples

  • We see the bat hit the ball before the crack is heard

  • Shouting and hearing your echo



Wave Front


  • A wavefront is a line or surface, in the path of a wave motion



We also had a worksheet for homework. It's called waves #1!














5 comments:

Larry Wirth said...

Adriana - Fantastic job on your scribe post - it's obvious you spent a lot of time putting it together, including additional research for the details and graphics.

Paul said...

Wow Adriana...I almost do not even want to do a blog after looking at yours ha no way I can do as well as you did. Solid job, the pictures help.

ange said...

wow this is a really impressive blog... i really liked the color usuage and the pictures really helped.

larissaloss said...

The pictures really helped me understand the information during this day and really helped me review for the quiz tomorrrow.

larissaloss said...

The pictures really helped me understand the information during this day and really helped me review for the quiz tomorrrow.