Lightning provides a powerful display of electrical energy.
How much does it cost to operate common appliances?
After reading Sections 20.2 and 20.3, you should be able to calculate the energy cost of operating electric appliances. Choose an electrical device that you use at home (for example, a computer or hair dryer), and ?nd out its power rating. Estimate how many hours per day you use it, and calculate the energy consumed in kilowatt-hours. Look up the cost of a kilowatt-hour in your area to determine how much the device costs to operate each day. Post your results on a class blog or wiki.
How do science concepts apply to your world? Here are some questions you'll be able to answer after you read this chapter.
Why do you sometimes feel a shock if you walk across carpet on a winter day and then touch a metal door handle? (Section 20.1)
What causes lightning? (Section 20.1)
How does a battery enable a flashlight to light? (Section 20.2)
Why do some appliances use three-prong plugs? (Section 20.3)
How do computers process data? (page 614)
How is information stored on a DVD? (Section 20.4)