Waves and Their Applications in Technologies for Information Transfer

High School students who demonstrate an understanding of Waves and Their Applications to Technologies for Information Transfer can:
 

PS4.A Wave Properties

PS4.A.1
The wavelength and frequency of a wave are related to one another by the speed of travel of the wave, which depends on the type of wave and the medium through which it is passing.
 




PS4.A.2
Information can be digitized (e.g., a picture stored as the values of an array of pixels); in this form, it can be stored reliably in computer memory and sent over long distances as a series of wave pulses.
 



PS4.A.3
Waves can add or cancel one another as they cross, depending on their relative phase (i.e., relative position of peaks and troughs of the waves), but they emerge unaffected by each other. 
 




PS4.A.4
Geologists use seismic waves and their reflection at interfaces between layers to probe structures deep in the planet.
 



 

PS4.B Electromagnetic Radiation

PS4.B.1
Electromagnetic radiation (e.g., radio, microwaves, light) can be modeled as a wave of changing electric and magnetic fields or as particles called photons. The wave model is useful for explaining many features of electromagnetic radiation, and the particle model explains other features.
 



PS4.B.2
When light or longer wavelength electromagnetic radiation is absorbed in matter, it is generally converted into thermal energy (heat). Shorter wavelength electromagnetic radiation (ultraviolet, X-rays, gamma rays) can ionize atoms and cause damage to living cells.
 


PS4.B.3
Photoelectric materials emit electrons when they absorb light of a high-enough frequency.
 

PS4.B.4
Atoms of each element emit and absorb characteristic frequencies of light. These characteristics allow identification of the presence of an element, even in microscopic quantities.
   

PS4.C Informational Technologies and Instrumentation

PS4.C.1
Multiple technologies based on the understanding of waves and their interactions with matter are part of everyday experiences in the modern world (e.g., medical imaging, communications, scanners) and in scientific research. They are essential tools for producing, transmitting, and capturing signals and for storing and interpreting the information contained in them.