Lesson 4 Introduction
What if cars no longer needed to be filled with gasoline? What if we could plug our cars in and run them on electricity instead? We can do that already! In some cities, charging stations are available for electric cars similar to gas stations for regular cars.
Every year, more electric cars are being used. These cars show how flexible electricity is—we can use it to do so many things.
The key to electricity’s usefulness is how easily the energy in electricity can be changed to various forms. Electrical energy can be changed into heat, light, movement, radio waves, sound, and even chemical energy! Many devices do more than one of these changes at the same time.
Read Electric Toasters to better understand how a toaster turns electric energy into heat.
Electric ToastersClick on each row to see an example of the device and the type of energy it uses.
An electric fan changes electrical energy into motion. Most of the time, this is done by an electric motor. When electricity runs through an electric motor, it spins.
Many devices use electric motors to make motion, such as blenders, electric lawn mowers, vacuum cleaners
A laser changes electrical energy into light. Lasers have a gas inside that is energized by electricity so that it glows.
Many devices turn electricity into light, such as light bulbs, light tubes, and the screens in television sets, computer monitors, and mobile phones.
An arc welder uses large amounts of electricity to produce very high heat that can melt and join metal.
Many devices turn electricity into heat, such as electric heaters, kitchen stoves, toasters, hair dryers, coffee makers, waffle irons, and electric kettles.
A speaker uses electricity to make vibrations that produce sound. If you put your hand on a speaker, you can feel the vibrations.
Many devices turn electricity into sound, such as headphones, bullhorns, buzzers, electric guitars, electric pianos, car alarms, fire alarms, and burglar alarms.
Some batteries can be recharged when they are connected to electricity. Inside the battery, energy is stored in the form of chemical energy. When the battery is used, the chemical energy is turned back into electricity. This back-and-forth energy change can be done hundreds of times before the battery wears out.
Many devices use rechargeable batteries, such a mobile computers and phones, music players, tools, and toys.
Electricity can be changed into invisible radio waves. These waves transmit information from place to place.
Many devices turn electricity into waves (and back again) for communication, such as radio stations, wireless computer networks, cordless and mobile phones, remote controls, GPS systems, and television satellite dishes.