Video Demo: Constant Speed Car

Speed is the rate at which an object covers a distance.  How do you know if that rate changes or not?  The video shows how to determine if the speed of an object is constant.

Video Demo: Accelerometer

Velocity is speed in a given direction.  How is a change in velocity (acceleration) detected?  Accelerometers.  Most smartphones have accelerometers to detect changes in velocity to monitor certain tasks.  The video demonstrates a very basic accelerometer and how it works.