P5 - Fluid Pressure

What is pressure?

The force per unit area.

What are fluids?

Substances that can flow because their particles can move around.

What is the particle theory behind pressure in fluids?

As particles move around, they collide with surfaces and other particles, exerting a force on them.

What is the equation linking pressure, force and area?

pressure (Pa) = force (N) / area (m²), or p = F/A

What factors affect the pressure in a liquid?

Density and depth.

How does density affect pressure in a liquid?

Density is how close particles are to each other, so a more dense liquid has more particles in a certain place. The number of particles in the column of liquid above a certain point is higher for a more dense liquid, and the weight of these particles adds pressure to that point, so liquid pressure increases with density.

How does depth affect pressure in liquids?

Going to a deeper point in a liquid increases the number of particles above that point, so the weight of these particles adds pressure, so liquid pressure increases with depth.

What is the equation linking pressure, height of column liquid, gravitational field strength and density?

pressure (Pa) = height (m) * density (kg/m³) * gravitational field strength (N/kg), or p = hρg