PS4.A: Wave Properties


In this video Paul Andersen describes some of the properties of waves.  He starts be identifying particles and waves as the only phenomenon that can transfer energy from place to place.  He identifies the defining characteristics of waves; wavelength, frequency and amplitude.  He defines sound as the movement of compressional waves through air and resonance as waves interfering both constructively and destructively.  A teaching progression K-12 is also included.

CCC7: Stability and Change


Paul Andersen explains how stability and change are regulated in systems through controls and feedback.  Controls are used to regulate matter and energy flowing into a system.  Feedback mechanisms within the system are used to regulate stability.  Negative feedback loops keep the values around a set point and positive feedback loops move them away.  Disequilibrium can result in death of living systems and destruction of physical systems.  A progression of instruction for K-12 students is also included.