Warm Up 1. What is energy? 2. What is chlorophyll? 3. What is ecology? 4. What is cellular respiration? 5. How does a plant get fertilized?

Energy

Energy Conservation **Energy is a conserved quantity. **This provides powerful constraints on what can and cannot happen in nature. This is an extremely important concept, and we will come back to this over and over throughout the remainder of the course.

What is Energy Energy: The capacity for doing work (or to produce heat) What are some forms/types of energy? 1. Mechanical (kinetic and potential energy) 2. Heat 3. Electricity 4. Electromagnetic waves 5. Sound 6. Nuclear 7. Chemical 8. Mass Energy: The capacity for doing work (or to produce heat) What are some forms/types of energy? 1. Mechanical (kinetic and potential energy) 2. Heat 3. Electricity 4. Electromagnetic waves 5. Sound 6. Nuclear 7. Chemical 8. Mass

The thing about energy is that it cannot be created or destroyed, it can only be transformed from one form into another

***Kinetic Energy – Energy of Motion Kinetic energy (KE) refers to the energy associated with the motion of an object. The kinetic energy is simply: KE = (½)mv 2 where m = mass in [kg], and v = velocity of object in [m/sec] What are the units of KE? [KE] = [mass] [velocity] 2 = [kg*m 2 /s 2 ] == [Joule] or just, [J] A Joule is a substantial amount of energy! Kinetic energy (KE) refers to the energy associated with the motion of an object. The kinetic energy is simply: KE = (½)mv 2 where m = mass in [kg], and v = velocity of object in [m/sec] What are the units of KE? [KE] = [mass] [velocity] 2 = [kg*m 2 /s 2 ] == [Joule] or just, [J] A Joule is a substantial amount of energy!

Potential Energy- stored energy An object can store energy as the result of its position. Examples: gravitational PE, elastic PE, –For example, the heavy ball of a demolition machine is storing energy when it is held at an elevated position. This stored energy of position is referred to as potential energy.

Gravitational PE PE related to an objects height. –GPE=Weight X Height Greater the weight, or height, the more GPE the object has.

Chemical Energy  PE stored in the chemical bonds that hold chemical compounds together.  Stored in the foods we eat (calories), matches you use to light a candle, and even the cells in your body.  PE stored in the chemical bonds that hold chemical compounds together.  Stored in the foods we eat (calories), matches you use to light a candle, and even the cells in your body.

Nuclear Energy  PE stored in the nucleus of an atom.  Nuclear energy is released during a nuclear reaction  For example, nuclear fission, that occurs when a nucleus splits.  Nuclear power plants use fission reactions to produce electricity.  PE stored in the nucleus of an atom.  Nuclear energy is released during a nuclear reaction  For example, nuclear fission, that occurs when a nucleus splits.  Nuclear power plants use fission reactions to produce electricity.

Mass Energy According to Einstein’s Theory of Special Relativity, Mass is a form of Energy, and they are related by the simple and well-known formula: E = mc 2 M=Mass C= Speed of light C = 3.0 X 10^8 m/s

E=mc 2  The important point here is that energy and mass are really equivalent, and are related to one another by simply the speed of light (c) squared!  This equation implies that even if a particle is at rest, it in fact does have a “rest-mass energy” given by this formula.

Can energy change from one type of energy to another? Nuclear Chemical (photosynthesis) Kinetic Thermal (maintain body temp) Electrical ( brain/nervous system)

Chemical (gas) Electric (engine) Sound Thermal Electromagnetic Mechanical

Solar Chemical (oil) Electrical Kinetic Nuclear Chemical Electromagnetic (light, microwave) Thermal Kinetic Sound (radio)

Electricity  Electricity generally refers to the flow of charges.  In most cases, electrons are the charges which are actually moving.  Charges are made to flow by applying a voltage  Batteries  Power Supplies  Electrical generators