Non-repeating wave, single disturbance.
I. Periodic wave
Regularly repeating disturbances.
J. Transverse wave
Spring is pulled sideways, and the wave across the spring to the direction that the wave will travel.
K. Longitudinal wave
Spring are compressed and let go, Disturbance is in the same direction as the direction of travel.
L. Destructive interference
The energies combine to work against each other as the periodic wave, the crest and trough tend to cancel out when two waves meet.
The video is the same as periodic wave.
M. Constructive interference
When two same size crest or trough meet from different direction, the energy of two wave combine to form a bigger wave when they meet.
have the same amplitude and wavelength, the resultant interference pattern remains nearly stationary. A node/nodal point remains at rest throughout the interference of the pulses.