I.S

• Temperature


  Tells us how warm and cold an object is
• Temperature scales


  • Kelvin (K)
  • Degrees Celsius (℃)
  • Fahrenheit (℉)
• Converting temperature scales


  1. C = 5/9(F - 32)

  2. F = (9/5)C + 32

  3. K = C + 273
• Heat


  The energy that flows from a higher-temperature object to a lower-temperature object due to temperature differences
• Higher temperature = more internal energy
• Thermal equilibrium


  Two objects are in close contact and one gains energy from the other without net energy transferred and no more change in temperature
• Modes of Heat Transfer

  • Conduction
  • Convection
  • Radiation
• Conduction


  • Direct contact is used to transfer heat
  • Metals are good conductors; plastic, wood, and other materials are poor conductors
  • Solids are better conductors than liquid and gases
• Convection


  • Fluids is the medium of how heat passes through
  • Convection current: hot fluid less dense causing it to rise and the cooler fluid denser causing it to sink down
• Radiation


  • Heat moving in waves
  • Does not need molecules (empty space) to pass the energy
  • Sun is main source
• Specific Heat Capacity


  Quantity of heat required to change the temperature of a unit mass
• Calculating Specific Heat Capacity

  1. Find the given

  2. Subtract the final temperature from the initial temperature to get the change in temperature (T)

  3. Use formula: C= Q/mT
• Other formulas for heat transfer

  • Tf = q/cm + ti
  • Ti = q/cm - tf
  • C = q/mt
  • M = q/tc
  • Q = cmt
• Thermal energy


  Another name for heat energy
• Temperature where there is no kinetic energy: 0 Kelvin
• Thermal Expansion


  Tendency of an object to change in length, area, and volume due to changes in temperature
• Coefficient of linear expansion, α


  Amount by which a material changes in unit length for every degree rise in temperature
• Calculating thermal expansion


  1. Linear: ∆L = αL∆T

  2. Volume: ∆V = 3αV∆T or βV∆T

  3. Area: ∆A = 2αA∆T
• Phase Changes


  • Exothermic: heat released
  • Endothermic: heat absorbed
  • Latent heat of fusion (Lf) - solid to liquid or vice versa
  • Latent heat of vaporization (Lv) - liquid to gas or vice versa
• Calculating latent heat


  1. Q = mLf

  2. Q = mLv
• Work


  Can be defined in terms of applied force and displacement
• Conditions for work


  • There must be a force acting on the object
  • The object must be displaced
  • The direction of the displacement must be the same with the direction of the force acting upon the object
• Work


  • F x D or MGD; unit is Joules (J)
  • Scalar quantity
• Types of work


  • Positive: component of the force is in the same direction as the displacement
  • Negative: component of the force is in the opposite direction as the displacement
• Power


  • Work done/time
  • Scalar quantity
  • Unit: Watts (W)
• Energy


  Physical quantity that enables a person or an object to do work
• Forms of mechanical energy

  • Kinetic Energy - energy possessed by moving bodies
  • Potential Energy - energy possessed by a body due to its position or condition
• Kinetic Energy


  KE = 1/2mv²
• Gravitational Potential Energy


  PEg = mgh
• Elastic Potential Energy


  PEs = 1/2kx²
• Work-energy theorem


  The work done by a force on an object is equivalent to a change in its kinetic energy
• Calculating work done on an elastic object

  Fs = kx
• Hooke's Law (Robert Hooke)
• Mechanical Energy


  ME = KE + PE
• Initial Energy


  PEi + KEi = PEf + KEf
• Energy Conversion: no energy is lost, it will only change form; inverse relationship between kinetic and potential
• 10% energy obtained by next organism, 90% for growth and performing metabolic and physiological processes
• Organisms consumed will not all be digested because some of the body became waste such as feces
• Energy carrying molecules by predators are used for metabolic processes instead of being stored as biomass