your mission Water covers more than 70 percent of Earth’s surface People use water for drinking watering crops transporting goods and more People also use the power of moving water to produce energy Your mission is to investigate water power as an energy source What kind of energy does water power give us How did humans use water power in the past How do we use water to produce energy today How might we use water power in the future Read the facts in What You Know Then start your mission to learn more about the exciting world of water power what you know (cid:204) More than 80 percent of the energy we produce comes from fossil fuels such as oil coal and natural gas (cid:204) Fossil fuels take millions of years to make and they create greenhouse gases when they are burned (cid:204) Energy from moving water is clean and renewable (cid:204) We can use rivers ocean waves and tides as sources of energy 4
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(cid:46)(cid:66)(cid:83)(cid:68)(cid:73)(cid:1)(cid:18)(cid:25)(cid:27) Yesterday’s Water Power I’m kicking off my research by visiting my older sister’s middle school Her science teacher Mr Donovan has offered to teach me the basics of water power He begins by telling me how past cultures have used water power as an energy source Water power may be considered an alternative energy source today Mr Donovan begins But humans have been harnessing the power of water for longer than you might think Ancient records are fuzzy but historians believe the ancient Chinese used water power to grind grain more than 2,000 years ago Romans were the first to write about water-powered wheels In the 300s CE Romans used 16 waterwheels to grind grain in what is now southern France Waterwheels were an important source of energy throughout Europe from the 1000s on Mr Donovan picks up a small pinwheel from his desk as he talks Waterwheels work a lot like this pinwheel I’m holding The pinwheel spins as he blows on it Air turns this pinwheel like water turns a waterwheel The mill uses the energy of motion This type of energy is called kinetic energy The kinetic energy of the 6
(cid:58)(cid:70)(cid:66)(cid:83)(cid:84)(cid:1)(cid:66)(cid:72)(cid:80)(cid:13)(cid:1)(cid:73)(cid:86)(cid:78)(cid:66)(cid:79)(cid:84)(cid:1)(cid:68)(cid:66)(cid:81)(cid:85)(cid:86)(cid:83)(cid:70)(cid:69)(cid:1)(cid:88)(cid:66)(cid:85)(cid:70)(cid:83)(cid:1)(cid:81)(cid:80)(cid:88)(cid:70)(cid:83)(cid:1)(cid:86)(cid:84)(cid:74)(cid:79)(cid:72)(cid:1) (cid:72) (cid:88)(cid:66)(cid:85)(cid:70)(cid:83)(cid:88)(cid:73)(cid:70)(cid:70)(cid:77)(cid:84)(cid:15)(cid:1)(cid:56)(cid:70)(cid:1)(cid:73)(cid:66)(cid:83)(cid:79)(cid:70)(cid:84)(cid:84)(cid:1)(cid:88)(cid:66)(cid:85)(cid:70)(cid:83)(cid:1)(cid:81)(cid:80)(cid:88)(cid:70)(cid:83)(cid:1)(cid:85)(cid:80)(cid:69)(cid:66)(cid:90)(cid:1)(cid:74)(cid:79)(cid:1) (cid:69)(cid:74)(cid:71)(cid:71)(cid:70)(cid:83)(cid:70)(cid:79)(cid:85)(cid:13)(cid:1)(cid:78)(cid:80)(cid:83)(cid:70)(cid:1)(cid:70)(cid:71)(cid:71)(cid:74)(cid:68)(cid:74)(cid:70)(cid:79)(cid:85)(cid:1)(cid:88)(cid:66)(cid:90)(cid:84)(cid:15) flowing water turns the stones of the waterwheel to grind the grain Mr Donovan explains that people began using hydropower or power harnessed from water power to generate electricity in the late 1800s By 1940 hydropower had become very popular At that time it provided 33 percent of U S electricity 7
