OOPS. This is a new one for me. Interesting demo, but... Museum or no museum, this would have been a little bit better demonstration if the tube did not project above the upper surface because actually, the low pressure is caused by an effect at the top of the tube rather than by the upper surface camber. On close scrutiny, it is the same effect as on the upper surface, but in detail it has this little inconsistency of being the curved path over the tube end rather than teh curve of the wing.... Licky, yes.... ... It is probably ok for third graders to show (or appear to show) them a lower pressure above a wing.
