Energy Goal: 6.P.3 Understand characteristics of energy transfer and interactions of matter and energy.

What is Energy? Work is done when a force moves an object through a distance. Energy is the ability to do work or cause change. When an object or person does work on another object, there is some energy transferred to that object. Energy is measured in Joules just like work.

Power and Energy If the transfer of energy is work, then power is the rate at which energy is transferred, or the amount of energy transferred in a unit of time. The less time it takes for energy to be transferred the greater the power. (think of the difference between a nice breeze moving a leaf and a hurricane moving a leaf) Power = Energy Transferred Time

Two basic kinds of energy are kinetic and potential energy.

Kinetic Energy Energy an object has due to its motion Depends on the mass and the velocity of an object. Kinetic energy increases as velocity increases and if mass increases. Changing velocity has a greater effect on kinetic energy than mass does.

Potential energy Energy that is stored and held in readiness is called potential energy. When you raise a book or compress a spring, you give the object potential energy. Potential energy that depends on height is gravitational potential energy. Gravitational Potential Energy = weight x height

Gravitational potential energy Potential energy related to an object’s height. Is equal to the work done to lift it GP= weight x height Example: a person weighing 125 pounds standing on the third floor of a building has more gravitational potential than a person of the same weight standing on the 1st floor.

Gravitational Potential Energy

Elastic potential energy The potential energy associated with objects that can be stretched or compressed. The further back an elastic is pulled the greater the potential energy.

Forms of Energy Mechanical energy is the energy associated with the motion or position of an object. Mechanical energy can be kinetic or potential. You can find an object’s ME by adding KE and PE.

Forms of Energy (Cont.) Forms of energy associated with the particles of objects include thermal energy, electrical energy, chemical energy, electromagnetic energy, and nuclear energy.

Thermal Energy The total potential and kinetic energy of particles in an object. When the thermal energy of an object increases, the object becomes warmer.

Chemical Energy Stored in chemical compounds It is potential energy stored in chemical bonds that hold chemical compounds together.

Other Forms Moving electrical charges produce an electric current, and the energy they carry is called electrical energy. Nuclear energy is potential energy stored in the nucleus of an atom. Electromagnetic energy, such as light, travels in waves that have some electrical and magnetic properties. Because waves move, they have KE.

Questions What is done when a force moves an object through a distance? A. force B. work C. energy D. none of the above

Energy that is stored and held in readiness is called ________________ Energy that is stored and held in readiness is called ________________. A. potential energy B. kinetic energy C. mechanical energy D. chemical energy

______________ energy increases as velocity increases and if mass increases. A. mechanical B. chemical C. kinetic D. potential