Presentation on theme: "Energy Conversions and Conservation"— Presentation transcript:
1Energy Conversions and Conservation Chapter 9 sections 2-3
2Types of Heat TransferConvection – transfer of thermal energy by the movement of a liquid or gasConduction - Particles from a warmer object transfer by colliding with particles from the cooler object.Radiation - Thermal energy transferred through electromagnetic wavesVisible light, ultraviolet, infrared, x-rays…..
3You Try! Convection, Conduction, or Radiation? Your feet get burned when crossing hot pavement barefootYou feel heat from the iron without touching itYour face tingles and feels warm when sitting out in the sunWhen the heater is running, your room on the second floor feels warmer than downstairs.
4What are energy conversions? A change from one form of energy to another.Chemical/Potential energy in food is converted into kinetic energy when you are active AND thermal energy to maintain your body temperature.Potential energy of the skater is converted into kinetic energy as he moves down the half-pipe.
6Energy Conservation in Plants Photosynthesis uses energy from the SUN to make new substances that have chemical energy…light energy is changed into chemical energy…Light energy comes from the sun plants change it into chemical energy you body changes it into another chemical energy when you eat it your body changes it to kinetic energy to function
7Law of Conservation of Energy Energy cannot be CREATED or DESTROYED! It is just converted into other forms of energy.Where does the Energy go??1. Friction: force thatopposes motionbetween twotouching objects2. Some energy istransferred intothermal energy
8Remember the bouncing ball lab?? When you dropped the ball, its bounce height was lower than the original drop height. WHY???
9ANSWER…The potential energy at the top was converted to kinetic energy as it dropped. When the ball hit the floor, some of the energy was released as FRICTION and thermal energy fromthe friction! Some energy alsochanged into sound energy!Therefore, it didn’t haveenough energy to bounceback to its original height.