McGraw-Hill Mathematics: Grade 4, Chapter 6

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From Water Power to Electric Power

Water Use in the United States
http://ga.water.usgs.gov/edu/wateruse.html

Visit this Web site to find out more about hydroelectric power.

• Read about water use. Then click Hydroelectric power.
• Read the paragraphs about hydroelectric power water use.
• Then scroll down. Next to "Data Table," click Hydroelectric water use.
• Use the information in the table's last column, "Gallons of water to produce 1 kilowatt-hour," to solve the problems.

1. How many gallons of water were used in California to produce 23 kilowatt-hours of electricity?
   
              gallons
   
   
2. How many gallons of water were used in Maine to produce 30 kilowatt-hours of electricity?
   
              gallons
   
   
3. How many gallons of water were used in Tennessee to produce 50 kilowatt-hours of electricity?
   
              gallons
   
   
4. An iron uses 1 kilowatt of electricity per hour. Pedro, who lives in Alaska, ironed for 10 hours. How many gallons of water were needed to produce the amount of electricity that the iron used?
   
              gallons
   
   
5. A washing machine uses 4 kilowatts of electricity per hour. Amelia, who lives in Oregon, washed clothes for 3 hours. How many gallons of water were needed to produce the amount of electricity that the washing machine used?
   
              gallons
   
   
6. An electric cooker uses 10 kilowatts of electricity per hour. Tom, who lives in Montana, used a cooker for 2 hours. How many gallons of water were needed to produce the amount of electricity that the cooker used?
   
              gallons
   
   
7. An electric grill uses 1 kilowatt of electricity per hour. Maya, who lives in New Hampshire, used an electric grill for 11 hours. How many gallons of water were needed to produce the amount of electricity that the grill used?
   
              gallons
   
   
8. A dishwasher uses 2 kilowatts of electricity per hour. Sam, who lives in Washington, used a dishwasher for 5 hours. How many gallons of water were needed to produce the amount of electricity that the dishwasher used?
   
              gallons
   
   

Math at Home

Today I explored a Web site that showed how water could be used to make hydroelectric                . I learned that the amount of water needed to produce one kilowatt-hour of electricity varies from state to state! I calculated the number of gallons of water needed to produce enough electricity to operate different electrical devices for different lengths of time. For instance, if Pedro lives in Alaska and irons for 10 hours,                 gallons of water are needed to produce the amount of electricity that the iron uses.

Ask your teacher or parents to show you other fun and interesting Web pages.