# IGCSE PHYSICS: chapter 19- density and pressure

HideShow resource information
• Chapter 19: density and pressure
• density, ? = mass, m / volume, V
• Density is measured in kg/m³.
• To convert from kg/m³ to g/cm³ times by 1000.
• volume = w (width) x h (height) x d (depth)
• pressure, p = force, F / area, A
• Pressure is measured in Pa = pascals
• It is the weight in newtons per metre squared acting down on a surface.
• 1 Pa = 1 N/m²
• In stationary liquids and gases the pressure increases with the depth of a gas or liquid.
• Pressure difference, p, in Pa = height in m x density in kg/m³ x gravitational field strength in N/Kg
• To find the density of an irregular shaped object.
• 1. Weigh the density of the object.
• 2. To find its volume, fill a can with a pout with water until it just flows out of the spout.
• 3. Place a clean, dry measuring cylinder beneath the spout.
• 4. Slowly lower the irregularly shaped object into the can until it is completely submerged.
• 5. The water displaced will have the same volume of that of the object.
• So the volume of the object is found by measuring the volume of the water collected in the measuring cylinder.