The period is the time between successive maxima. The frequency is the number of maxima that pass per second. The phase tells us how far through a cycle something is. Reflection occurs when a surface throws back the heat, light, sound etc that falls on it. Refraction is the change of direction that occurs when the medium changes.
Diffraction occurs when a wavefront bends near a gap or an edge in the same medium.
Interference occurs when waves pass through each other at a point in space and the result at that point is the sum of the wave heights. Polarisation occurs for transverse waves when the vibration directions are not randomly oriented. Sound is produced from a sudden local compression of a gas, liquid or solid. An ultrasonic transducer is a device that changes its physical size when an electric potential is applied to it. At an interface there is reflection, transmission and absorption.