Chapter 8 Comprehensive Science 2 Lesson 1 Forms

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. 5 kg and another weighs 5. 5 kg…. . 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

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

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

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 1. 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 2. Radiation: Transfer of thermal energy by electromagnetic wave a. Example: Thermal energy is transferred out of hot water by radiation and conduction 3. 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