What is the law of conservation of energy? How is energy transformed and transferred? What are renewable and nonrenewable energy resources? Energy Transfers and Transformations

The law of conservation of energy says that energy can be transformed from one form to another, but it cannot be created or destroyed.law of conservation of energy Law of Conservation of Energy

The law of conservation of energy indicates that the amount of radiant energy that shines out of the flashlight cannot be greater than the chemical energy stored in the battery.

When energy moves from one object to another without changing form, an energy transfer occurs.energy transfer The mechanical energy of a tennis racket changing the movement of the ball is an example of an energy transfer. Law of Conservation of Energy (cont.)

When one form of energy is converted to another form of energy, an energy transformation occurs.energy transformation The conversion of chemical energy stored in a tennis player’s muscle changing to mechanical energy when she swings her arm is an example of an energy transformation. Law of Conservation of Energy (cont.)

Because energy transformations/transfers are inefficient, some of energy transforms to thermal energy that is released to the environment. An open system is a system that exchanges matter or energy with the environment.open system A closed system is a system that does not exchange matter or energy with the environment.closed system In reality, there are no closed systems because every physical system transfers some energy to or from its environment. Law of Conservation of Energy (cont.)

A renewable energy resource is an energy resource that is replaced as fast as, or faster than, it is used.renewable energy resource Solar energy from the Sun is one type of renewable energy resource that can be converted into electric energy. Energy Transformations and Electric Energy

Wind moves the blades of a wind turbine to generate electric energy. In hydroelectric plants, falling water is channeled through a turbine which transforms mechanical energy into electric energy. Energy Transformations and Electric Energy (cont.)

Geothermal plants transfer thermal energy from the Earth to water, creating steam that turns turbines in electric generators. Biomass includes wood, plants, manure, and garbage, all of which are sources of stored chemical energy that can be transformed to electric energy in energy plants. Energy Transformations and Electric Energy (cont.)

Nonrenewable energy resources are energy resources that are available in limited amounts or that are used faster than they can be replaced in nature. Nonrenewable energy resources Fossil fuels include petroleum, natural gas, propane and coal. In nuclear energy plants, uranium atoms are split apart in a process called nuclear fission. Energy Transformations and Electric Energy (cont.)

Most of the energy used in the United States comes from nonrenewable energy resources.