Comprehensive Science 2 Chapter 8 Comprehensive Science 2

Lesson 1 Forms of Energy

Energy Any way in which we cause change Examples: Eating before working out Pushing an object Pulling an object Turning a light on Plants converting sugar to energy

Potential Energy Stored energy The brief moment in which an object has the “potential” to have energy Examples: Rock at the top of the hill Rubber band before it is stretched Moment before object is let go

Gravitational Potential Energy Anything that has mass and height above earths surface Dependent on the mass of an object and the distance an object is to earth Examples: ANYTHING!!!

Chemical energy Energy that is stored and released through chemical bonds Examples: When your body takes food that is eaten and converts it into energy Batteries Cracked glow sticks

Nuclear Energy Energy stored and released in the nucleus Examples: Sun setting is nuclear energy because the rays that are reflected is occurring via nuclear fission When an atom breaks apart Nuclear fusion Nuclear fission

Kinetic energy Energy of motion Examples: Ball rolling down the hills Rubber band being let go

Kinetic energy of motion The amount of kinetic energy an object has in relation to speed For example, If you have two objects and object one weighs 3.5kg and another weighs 5.5kg….. Both have the same speed, however the heavier object has more kinetic energy

Electric Energy Any type of energy in an electric current Example: Copper wire attached to a battery

Mechanical Energy Sum of potential energy and kinetic energy

Thermal Energy Sum of kinetic energy and potential energy

Wave A disturbance that transfers energy from one object to another Examples: A rock falling in a pond of water Dominos that knock each other over

Sound Energy Energy that is carried through sound waves Examples: Radio Earphones Speakers

Radiant energy When energy is carries via electromagnetic waves Examples: Light Different rays emitted by light

Activity!! ENERGY PAMPHLET ACTIVITY

Energy Transfers and Transformation Lesson 2 Energy Transfers and Transformation

Law of Conservation of Energy Energy cannot be created nor destroyed Energy CAN be transferred and transformed

Energy Transfer Energy moves from one object to another, but does not change form Tennis ball example: Tennis player hits ball Mechanical energy in racket changes movement of the ball Mechanical energy of the ball increases after it is hit Write down in your notes another example of Energy Transfer

Energy Transformation When energy is converted to another form of energy Tennis example: The mechanical energy in the racket and tennis ball comes from somewhere… Chemical energy from the tennis player’s muscle TRANSFORMS into mechanical energy

Energy and Work Simply put…. Work is energy transferred by force Example: Pushing a heavy shopping cart for 10 m You lift your school bag upwards by 1 m Work = Force x Distance Tennis example

Inefficiency of Energy Transformations Anytime an energy transformation or transfer takes place, some energy is transformed into thermal energy When force is applies or work occurs there is a certain percentage that is lost because it can be converted into sound energy or thermal energy

Inefficiency continued Energy transformations are inefficient because not all energy that is transformed to another form is usable

A system that exchanges matter or energy with the environment Open Systems A system that exchanges matter or energy with the environment Write examples in your notes.

A system That does not exchange matter or energy with the environment Closed systems A system That does not exchange matter or energy with the environment Can you think of any examples?

Renewable resources VS. Nonrenewable resources

On your own… What energy transformations occur in a wind turbine? Identify an energy transfer and an energy transformation that occur when someone plays guitar.

Lesson 3 Particles in Motion

Kinetic Molecular Theory Explains how particles move 1. All matter is made of particles 2. Particles are in constant, random motion 3. Particles constantly collide with each other and with the walls of their container

Heat Transfer Conduction: is the transfer of thermal energy by collisions between particles in matter a. Example: Thermal energy from the burner is transferred into water by conduction Radiation: Transfer of thermal energy by electromagnetic wave a. Example: Thermal energy is transferred out of hot water by radiation and conduction Convection: transfer of thermal energy by the movement of the particles from on part of a material to another a. Examples: cycles of rising and sinking water transfer thermal energy throughout water by convection

Ending of Ch. 8 Changes between solids and liquids Melting Freezing Changes between liquids and gases Vaporization Boiling and evaporation Changes between solids and gases Sublimation and deposition Conductors vs. Insulators