Five minutes, presented by Nikhil Mistry, from the ISVR at the University of Southampton — a genuine acoustics research institute rather than a general science channel. The build is a home tonoscope, and the framing is deliberately participatory: the description invites viewers to send in photos and video of theirs working.
The explanation is compact and correct, running from Chladni bowing a plate through to why a driven membrane sorts powder onto nodal lines. Because it comes from an engineering department, the terminology is the terminology you will meet in the literature, which is not always true of maker-channel versions.
There is a companion video on their channel doing an experiment with instant coffee, linked in the description. Both are pitched at outreach level, so this is a good thing to send someone who has asked what you actually do with a tonoscope.