Energy

1. Energy store 能量库

   1. Kinetic
   2. Gravitational potential
   3. Elastic potential
   4. Chemical potential
   5. Internal (heat)
   6. Nuclear

2. Energy transfer

   1. Work down (mechanical)
   2. C,C,R (热)
   3. Waves
   4. Electrical current 不能用transform,只能用transfer

3. Non-renewable

   1. fossil fuel
      • disadvantage
        • pollution
      • advantage
        • cheap & reliable
   2. neuclear energy
      • disadvantage
        • pollution
      • advantage
        • cheap & reliable

4. renewable

   1. clean energy:wind,hydro,solar,tide,Geothernal
      • advantage
        • clean
      • disadvantage
        • non-reliable
   2. biomass
      • disadvantage
        • greenhouse gas