Physics IGCSE notes module 5:Solids, Liquids, Gases

Physics notes - Solids, liquids and gases notes




Density:
 Equation
 Density = mass/volume
 Or: ρ = m/v

How to calculate the density of an irregular object
 Eureka can
1. Use a eureka can/measuring cylinder nb 1ml = 1 cm2
2. Weigh the object
3. Put numbers into the equation
 Using a measuring cylinder:
 Measure volume before and after placing object in
 Density = mass/ Vol2-Vol1
 NB: Density can either be in g/cm3 or kg/m3

Pressure:

,  Equations
 Pressure = force/area
 P= F/A
 Pressure is measured in pascals
 1 pascal/ 1 Pa = 1N/m2

Gas pressure:
 The pressure In a liquid or a gas at a particular point acts equally in all directions

 The particle theory explains gas in the following way:
1. Gas molecules travel in a constant random motion
2. When a molecule collides with a surface it exerts a force on the surface as it changes direction
3. The pressure exerted by the gas is equal to the total force exerted by the molecules over an area of the
surface, divided by area.

 Can be increased by
 Increasing kinetic energy- heating
 Decreasing surface area

Pressure in liquids:
 The pressure In a liquid at a particular point acts equally in all directions
 What affects pressure
 The pressure in a liquid or gas increases with depth.
 Pressure depends on the density of the liquid/gas- higher density = higher pressure
 Pressure does not depend on the shape of the container
 Equation
 Pressure = density x height (how deep in the water) x gravity
 P= ρ gh
 The density of water is 1000N/m3