pressure in gasses

Question 1

how may pressure increase

Answer 1

1. because the container has been squashed making the volume smaller so that the particles will be hitting the walls more often.
2. because the number of particles has increased, so that there are more particles moving around to hit the walls.

Question 2

what does air pressure let you do

Answer 2

Air pressure lets you suck things up using a straw and also causes a container to collapse if the air is sucked out. if all the is sucked out of a container you get a vacuum (nothingness)