(5.3-5.7) Density + Pressure

State the formula for density.

mass / volume

m/V

Define density.

The mass per unit volume of a material.

Why are gases less dense than solids?

There are fewer particles in a given area.

Describe how to measure the density of an irregularly shaped object.

1. Measure mass of object.

2. Fill Eureka can with water up to just below spout.

3. Place empty measuring cylinder beneath spout.

4. Lower object into can and measure water displaced.

5. The volume of water = volume of object.

6. Repeat, average, calculate.

Describe how to calculate the density of a liquid.

1. Measure mass of measuring cylinder + liquid.

2. Subtract cylinder mass for mass of liquid.

3. Divide by volume of liquid.

What tool is used to measure the side lengths of objects?

Vernier Callipers

Define pressure.

The concentration of a force

Force per unit area

State the formula for pressure.

force / area

F / A

For a given force applied to 2 different areas, the smaller area will have a…

higher pressure.

How does pressure act in fluids at rest?

the pressure at any point is equally acting in all directions

How does pressure effact an immersed, stationary object in a fluid?

pressure is exerted evenly in all direction

pressure creates forces

that act at right angles to the surfaces.

State the formula for the pressure in a liquid.

P = h p g

height*density*gravitational field strength

Why is the formula for pressure in a liquid different than that for a solid?

the deeper an object,

the greater the mass of fluid above it and

the more molecules exerting pressure above it