All fluids exert pressure like the air inside a tire. The particles of fluids are constantly moving in all directions at random. As the particles move, they keep bumping into each other and into anything else in their path. These collisions cause pressure, and the pressure is exerted equally in all directions.
Observing is commenting on what you see e.g: It is raining.
Inferring is drawing conclusions from observations for example you see the road is wet so you might infer that it rained last night.
