Energy Transformations and Conservation Ms. D 7th Grade

Vocabulary Energy- The ability to do work or cause change. State- The form in which matter exists. Energy Transformation- A change from one form of energy to another, (also called energy conversion.) Law of Conservation of Energy- The rule that energy cannot be created or destroyed. Potential Energy- The energy an object has because of its position (internal stored energy of an object) Kinetic Energy- Energy that an object has due to its motion. Mechanical Energy- is the energy associated with the position, shape, or motion of an object.

How Does Heat Affect a System? Pg. 347 State- The form in which matter exists. Solid - A state in matter that has a definite shape and a definite volume. Liquid- A state in matter that has a definite volume but no shape of its own. Temp. at which liquid freezes into solid is called freezing point. Temp. at which liquid boils, turn into gas is called the boiling point. Gas- A state in matter has neither a definite shape nor a definite volume.

How Does Heat Affect a System? Pg. 348 Energy is the ability to do work or cause change. All states of matter (solid, liquid, and gas) contain energy. A state is the form in which matter exists. Heat + to a system= the temp. of substances in the system increases. Heat - from the system= temp. decrease. If enough heat is added to or removed from a system, substances in the system will change states. What will happen to the particles of a substance if heat is added?

How Does Heat Affect a System? Pg. 349 Basic types of energy: P__________ energy results from the position or shape of an object. (book on a shelf, k__________ energy, is the energy that results from the motion of an object. Together, p_________ energy and k_______energy make up mechanical energy.

How Does Heat Affect a System? All objects= made up of small particles called________ & ____. Thermal energy-is the total K.E and P.E of all the particles in an object. T.E. can be transferred from one object to another. T.E. is transferred from a hot object to a cool object. T.E. transferred is called_________.

What Forms of Energy Are Related to Particles? Pg. 350, 351 A type of potential energy called Nuclear energy is stored in the nucleus of an atom and is released during a nuclear reaction. Thermal energy is the total kinetic energy and potential energy of the particles in an object. The energy of electrical charges is called electrical energy. Electromagnetic energy travels through space in waves created by vibrating electrical charges. Chemical energy is potential energy stored in chemical bonds, which hold atoms to each other.

What Forms of Energy Are Related to Particles? Pg. 350, 351 Forms of energy related to the particles of objects: N_______ energy Type of P.E.(energy store in nucleus of atom) T________ energy Type of K.E.(Total Kinetic & Potential energy) E________ energy (energy of electric charges) e.g. lightning, batteries E_____________ energy (energy that travels through space in waves) C_________energy (Potential energy stored in chemical bonds) e.g. Food, matches

How is Energy Conserved During a Transformation? Pg. 352 All forms of energy can be transformed into other forms of energy. Change from one form of energy to another is called an energy transformation. Some energy changes involve one transformation. Others involve many transformations. Single transformations- one form of energy is transformed to another form to do work. e.g. Chemical energy in food  mechanical energy to move muscles Chemical energy in food  thermal energy to maintain your body temp.

How is Energy Conserved During a Transformation? Pg. 352 Multiple Transformation- a series of transformations is needed to do work. e.g. Car engine (Electric E.) produces a spark Thermal E. of spark releases Chemical E. in the fuel produces expansion and increased pressure Mechanical E.

How is Energy Conserved During a Transformation? Pg. 353,354 Most common type of energy transformation is between Kinetic E. and Potential E. Law of Conservation of Energy- The rule that energy cannot be created or destroyed. In a system, as energy is transformed it is neither lost nor created. Energy is conserved. (all the energy you had before the reaction is equal to all the energy you have after the reaction) The total amount of energy is the same before and after any transformation.

How is Energy Conserved During a Transformation? pg. 354 Friction is the force that one surface exerts on another surface when the two surfaces rub against each other. When parts of a moving system encounter friction, some of the kinetic e. f the system is transformed into thermal e. The energy of a system that is exposed to friction may decrease. But overall, energy in the system is neither lost nor created. In fact, the heat produced by friction is evidence that energy is conserved.