The Particle Model

• Density - ρ

  $ρ =$$mass/volume$
• Upthrust


  • An object floats in a fluid if the density of the object is lower than the density of the fluid.
  • The force that keeps the object afloat is called upthrust.
• Law of Displacement

  The Law of Displacement says that an object completely submerged in a fluid (like water) will replace an amount of fluid equal to its own volume

  
• If volume is fixed, increasing an object’s mass will increase its density.
• If an object floats...

  Its density must be lower than the density of the fluid
• Internal energy

  The total energy that's stored by the particles making up a substance or system
• Components of internal energy

  • Potential energy stores
  • Kinetic energy stores
• Kinetic energy

  The movement energy of the particles
• Heating up a substance


  Transfers energy to the kinetic energy store of all the particles, increasing their internal energy
• Temperature

  A measure of the average internal energy of a substance
• Specific heat capacity

  The amount of energy needed to raise the temperature of one kilo of a substance by one degree Celsius
• Specific heat capacity

  Change in internal energy (Joules) = mass (kg) x specific heat capacity (J/kg°C) x temperature change (°C)

  $ΔE =$$m c Δ θ$