1. ENERGY TRANSFORMATIONS Chapter 5----Section 2

2. Changing Forms Energy transforms continuously from one form to another Energy transforms continuously from one form to another Observed by change in our environment Observed by change in our environment

3. Tracking Transformations How would you describe this form of energy? How would you describe this form of energy?

4. 1. A biker pedals, his leg muscles transform chemical energy into kinetic energy 2. The kinetic energy of his muscles transforms into the kinetic energy of the bike as he pedals 3. Some of the energy transforms into potential energy as he gets higher up a hill 4. Some energy transforms into thermal energy since the chemical energy being released causes his body to get warmer 5. Friction caused by the bike also releases heat

5. The Law of Conservation of Energy Remember energy cannot be created or destroyed! Remember energy cannot be created or destroyed! The only change occurring is the form in which energy appears The only change occurring is the form in which energy appears Energy moves from place to place Energy moves from place to place The original amount of energy is always the same (it is always accounted for) The original amount of energy is always the same (it is always accounted for) Is used to track the energy changes in a system Is used to track the energy changes in a system

6. Changing Kinetic and Potential Energy Track the energy of throwing a ball in the air and catching it: Track the energy of throwing a ball in the air and catching it: P = 5 J K = 5 J P = 5 J K = 5 J P = 0 J K = 10 J P = 10 J K = 0 J P = 0 J K = 10 J

7. Transforming Chemical Energy Inside our bodies, chemical reactions take place that cause molecules to change Inside our bodies, chemical reactions take place that cause molecules to change Muscles contract, part of the body moves Muscles contract, part of the body moves chemical  kinetic energy chemical  kinetic energy Food – gives us energy when we digest the molecules Food – gives us energy when we digest the molecules chemical  thermal energy chemical  thermal energy Chemical energy breaks down when organisms die Chemical energy breaks down when organisms die Biomass = fuel from matter in living things Biomass = fuel from matter in living things Fossil fuels Fossil fuels

8. Transforming Electrical Energy Electrical energy is used daily Electrical energy is used daily Can be changed into: Can be changed into: Sound energy via waves Sound energy via waves Kinetic energy (speaker vibration or powered machines) Kinetic energy (speaker vibration or powered machines) Chemical (when sound reaches nerve cells) Chemical (when sound reaches nerve cells) Thermal (when a cord heats up) Thermal (when a cord heats up) Light/Radiant (powering a light source) Light/Radiant (powering a light source)

9. Transforming Thermal Energy Energy in the form of heat is almost always a product of an energy transformation Energy in the form of heat is almost always a product of an energy transformation Chemical  Thermal Chemical  Thermal Something being burned Something being burned Electrical  Thermal Electrical  Thermal Electric chord heats up Electric chord heats up Thermal  Kinetic Thermal  Kinetic Water boils into steam to energize steam engines (the steam turns the turbine) Water boils into steam to energize steam engines (the steam turns the turbine) Thermal  Radiant Thermal  Radiant Heated metal glows Heated metal glows

10. How Thermal Energy Moves Always from something with a higher temperature to something with a lower temperature Always from something with a higher temperature to something with a lower temperature Ex. From a warm cup to the air around it Ex. From a warm cup to the air around it HIGH TEMPERATURE LOW TEMPERATURE

11. Generating Electrical Energy We use an enormous amount of electrical energy daily We use an enormous amount of electrical energy daily POWER PLANTS: Usually the final 2 steps contain a: POWER PLANTS: Usually the final 2 steps contain a: Turbine- is a set of narrowly spaced fan blades that is turned by steam to power the generator Turbine- is a set of narrowly spaced fan blades that is turned by steam to power the generator Fossil fuels are burned to generate the steam Fossil fuels are burned to generate the steam Generator- a device that transforms kinetic energy into electrical energy Generator- a device that transforms kinetic energy into electrical energy Nuclear power plants operate similarly Nuclear power plants operate similarly

12. Power Plant Energy Flow Chemical Energy of Fossil Fuel (Coal) Thermal Energy of Water Kinetic Energy of Steam Kinetic Energy of Turbine Electrical Energy out of the Generator