 Energy – The work a physical system is capable of doing  Involves energy changing state Example: steam turns a turbine Example: gasoline burns in internal combustion engine Example: steer burns corn to make muscle

 Electricity  Mechanical energy  Chemical energy  Heat  Light Thermodynamics deals with the interrelationships between heat and other forms of energy

 The amount of energy in the universe remains unchanged  Energy cannot be created nor destroyed It can change form Example: water  steam

 C 6 H 12 O 6 + 6O 2  6 H 2 O + 6CO Kcal  The Kcal is the unit we use to measure energy  This means that we can measure heat to determine energy conversions in animals  Calorimetry is the measurement of heat produced or used during some process  Life  Combustion

SourceGross Energy (Kcal/g) Carbohydrate (4) Protein (5) Fat (9)