OBJ set 12

capacity to do work

• heat need to raise 1 gram of water to 1*C at 1 atm pressure
• ex. running 7 miles - 865 cal per hour

• (force) x (distance)
• energy expended by natural phenomenon
• transference of energy produced by the motion of a point where force has been applied

stored energy

• active energy
• energy currently being used

• involves physical movement
• anything held up against the force of gravity has potential energy
• as obhect falls kinetic energy is being expended

• involves chemical bonds between atoms
• energy stored in chemical bonds is a form of potential energy
• breaking these bonds rapidly by combustion or more slowly by chemical reactions release kinetic energy

• involves the flow of electrical charge
• concentration gradients of ions across a plasma membrane is a form of potential energy created in both nerve and muscle tissue
• nerve impulses are kinetic energy released as the ions flow across the plasma membranes

light energy

carry more energy ---> damaging effects of: ultraviolet light, x-rays, gamma rays, cosmic rays

• carry less energy
• infrared light = heat
• less usable form of energy

• plants convert light energy to chemical energy via photosynthesis
• muscles cells convert chemical energy to mechanical energy some of which becomes heat energy

matter is neither created nor destroyed 

• energy is neither created nor destroyed
• energy input always equals energy output

• quality of usefulness of energy always decreases 
• this degradation usually takes the form of heat energy lost to the surrounding environment