Chapter 3

Section 3: Technology improves the ways people use energy.

Review

Energy can be converted from one form to another.

Energy must be converted in order for it to be useful.

Law of Conservation states that energy it neither created or destroyed, from can change forms.

Energy Efficiency is a measure of usable energy after an energy conversion.

Energy

Because most energy conversions are very inefficient, an important goal of technology is to improve energy efficiency.

Different forms of technology are being developed and used to improve the efficiency of energy conversions.

LEDs

Regular light bulbs use up a lot of energy and are not very energy efficient.

Therefore LEDs (light-emitting diode) were created. They convert almost all of the electrical energy into light.

LEDs

LEDs

Regular light bulbs use up a lot of energy and are not very energy efficient.

Therefore LEDs (light-emitting diode) were created. They convert almost all of the electrical energy into light.

LEDs

Regular light bulbs use up a lot of energy and are not very energy efficient.

Therefore LEDs (light-emitting diode) were created. They convert almost all of the electrical energy into light.

Efficient Cars

Another common but inefficient energy conversion is the burning of gasoline in cars. A large percentage of gasoline’s chemical energy is not converted into the car’s kinetic energy.

Hybrid Cars

Hybrid cars, which use both a gasoline engine and electrical energy from batteries, are more efficient than conventional gasoline-powered cars.

Technology improves the use of energy resources.

Fossil Fuels are the most commonly used energy source, which is a non-renewable resource.

A major goal of technology research is a more efficient usage of other energy sources.

Solar CellsA solar cell is a device that converts the

energy of sunlight into electrical energy.

Solar Cell Panel

Solar energy is available in unlimited amounts, is quiet, clean, and nonpolluting.

However it is inefficient (only 12-15% energy conversion )and materials are expensive.

Solar Cell Car

Windmills

Windmills are used to convert the kinetic energy of the moving wind into electrical energy.

Like solar energy, it is an inexhaustible source of energy that is nonpolluting.

WindmillsHowever, it takes a large number of windmills to produce enough electrical energy to make a windfarm economically viable. Also, wind power is limited to certain regions.

Windmills

1. converts 5% of energy into light;

2. loses 95% of energy to heat; 3. not efficient; LED: 1

1. converts almost all energy into light; 2. used to transmit information; 3. . very efficient

LEDs convert almost all of their electricity to light.

LEDs are now being used in computers, outdoor signs, and traffic signals.

LEDs are also used to transmitinformation through fiber optic cables.

no; because an LED light converts almost all of its energy to light, there is little energy left to heat the bulb

fuel injectors and the manufacture of hybrid cars; More potential energy from the fuel is converted into the car’s kinetic energy.