constructive interference: when a wave is created on two sides of a medium, and then once it meets in the middle the wave becomes double the size of the two that met. they pass through each other, and then reduce down to their original sizes.
destructive interference: when two waves pass through each other but one is a trough and one is a crest, and once they meet, the briefly become flat in one spot. then they pass through each other and continue down the medium.
standing wave: a standing wave is when a medium is destructive but progressively gets faster and smaller, creating still spots called “nodes”. ours has 4 nodes which you can briefly see in the last few seconds of the video. this is also where the peaks do not move spatially.