why does the paper strip move upward when air is blown?

the paper strip moves upward because when we blow it we apply some force which makes the strip to move upward

 when we blow air above the paper strip,it causeas low pressure.this is because high speed wind is always accompanied by low pressure.the air from the high pressure area rushes to the top part of the paper and inthe process,the paper is also lifted up

Coz a low area is created above the paper and high pressure is created below the paper. This high pressure pushes the paper up.

• when we blow above the strip the air above it gets pushed so the air below it takes place that is why the strip moves upwards.
• high speed winds are accompanied by low speed winds.