Question

What do does a strip paper rise after blowing over it surface

Answer 1

moving air creates low pressure area making the paper strip to rise

Answer 2

Air's made of particles. And when these particles get blown around, other particles get sucked into the gap to maintain equilibrium. So when you blow across the paper, you're blowing particles away from the paper. This creates an area of low air pressure - where there aren't many particles over the paper. This makes the higher air pressured areas around your breath suck into the low pressured area - and one of these areas is the paper. So the paper gets sucked up to maintain equilibrium.

It's the same principle at work when you suck into a drinking straw or when you attach a sink plunger to the wall - the particles get sucked into the area to avoid creating a vacuum. Hope this helps!