3 ms·

I guess this is somewhat counter intuitive: https://www.youtube.com/watch?v=NBsvzMi9-f8 https://www.youtube.com/watch?v=NBsvzMi9-f8 So yeah, fans are puzzling

• stavros 3y ago
  That seems like the Coanda effect more than anything.
• convivialdingo 3y ago
  If you watch it very slowly, the paper initially folds under the mouth and then it blows out straight. I'm guessing the initial puff creates a high pressure area on top of the paper, rolling it downward and back. Them after the puff has pushed the air away, there is now a low pressure zone on top of the paper which lifts it up as the air below is rushing upwards around the sides of the paper.