- Renewable energy: solar, wind, hydroelectric, geothermal. can be reproduced. most have a quick start up time.
- Types of energy: light, heat, electric, chemical, kinetic, gravitational potential, elastic potential, sound, nuclear.
- Heat energy is transferred in three ways: conduction, convection, and radiation.
- Conduction is particles passing on their spare heat energy to nearby particles using collision and their free electrons. happens in solids, a bad conductor is called an insulator. metals are good conductors.
- Convection only happens in liquids and gases. it is all about the changes in density when heat is applied or removed to or from a set of particles. the density increases when the heat is removed and the density decreases because the particles condense. when heat is applied the particles spread out (disperse) and the density decreases.
- Radiation is a method of heat transfer that happens in everything. dull, black surfaces emit and absorb heat better than light, shiny surfaces which reflect heat energy.