1、How Tall is Your Tower?,Emily Kogut Physics 240 Spring 2011,Jenny is happy. Her best friend Sam is coming to her house to play. They will do many things.,Ding-dong. The doorbell rings. Jenny opens the door. “Hi Sam,” she says. “Hi Jenny!” Sam says.,“Ready to have fun?” asks Jenny. “Yes!” yells Sam.
2、Sam runs into the playroom.,Jenny follows Sam. “Lets build block towers,” she suggests. “Okay!” says Sam. “Mine will be taller.” “You just wait,” Jenny tells Sam.,Jenny starts building immediately. Sam does, too.,Jenny and Sam work for a long time. “Done!” Sam exclaims. “Me, too!” Jenny says. “Lets
3、see whose is taller,” Sam says.,Sam looks at the two towers. The towers are far apart. “How can we measure them?” Sam asks.,Jenny looks around the room. “I have some dolls,” she suggests. She picks up two dolls. “And I see cars,” Sam adds. He grabs a few cars.,“I finished first, so lets measure my t
4、ower first,” Sam says. “Okay!” Jenny says. She and Sam walk to his tower.,Sam puts one car at the bottom of his tower. “One,” he says. Jenny puts one car on top of Sams car. “Two,” she counts.,Sam puts moves his car so it is on top of Jennys car. “Three,” he counts. Jenny and Sam keep counting until
5、 the reach the top of Sams tower. “Four!” Sam says excitedly.,“My tower is four cars high,” says Sam. “Lets measure your tower.” Jenny and Sam go to her tower. Jenny stands one doll next to the bottom of her tower. “One,” she counts.,Sam puts the other doll on top of Jennys doll. “Two,” he says. “An
6、d this is the top.” “Oh,” Jenny says sadly. “Well, Sam, you win. Your tower is four cars tall, but mine is only two dolls tall.”,“It was a fun contest,” Sam says, “but I think we should have a snack before we do it again.” “Yes,” Jenny says. She and Sam run to the kitchen.,Sam and Jenny are eating a
7、pples. Jennys older brother, Kevin, walks into the kitchen. “Your towers are cool,” he says. “Congratulations, Jenny.”,Jenny stares at Kevin. She can not believe her ears. “Me?” she asks. “But Sams tower is bigger.” “Yeah,” Sam adds. “We measured them with cars and dolls.”,Kevin nods understandingly
8、. “Ah,” he says. “Ill be right back!” He runs to his bedroom. When he comes back, he has something in his hand. “Follow me,” he says. Jenny and Sam follow Kevin to the playroom.,“This is a ruler,” Kevin explains. “We use it to measure things with a standard unit of measurement.” Sam frowns. “What do
9、es that mean?”,Kevin smiles. “It means that everyone can agree on its measurements. The ways of measuring with it are the same no matter where you are or what you are measuring.”,=,“Oh,” Jenny says. She smiles. “So you mean that ours were not the same because we measured my tower with dolls, but we
10、measured Sams tower with cars.”,“Yes,” Kevin says. “Cars and dolls come in different sizes, so they are not standard. If I wanted to see whose tower was bigger using a racecar toy, I need to use the same racecar toy to measure both towers.”,“So?” Sam asks. “Whats wrong with that?” Kevin smiles. “Wha
11、t if everyone in your class built a tower? Or everyone in the school? It would take a long time to measure using only one racecar toy.”,“Then what can you use?” Sam asks. Kevin points to the numbers and lines on his ruler. “In science, we use the metric system. Each of these lines marks a centimeter
12、. We use centimeters to measure small things, such as racecar toys, dolls, and towers.”,“Lets try it!” Jenny exclaims. Kevin shows them how to hold the ruler. He places the bottom of the racecar next to the number zero on the ruler. “The number next to the top tells how tall the racecar is.”,“Eight,
13、” reads Sam. “The car is eight centimeters tall.” “Now lets measure my doll,” says Jenny. She takes the ruler from Kevin. “Make sure to start at zero,” says Kevin.,Jenny places the bottom of her dolls foot next to the number zero on the ruler. She looks at the top of the dolls head. “Twenty-five,” s
14、he reads. “The doll is twenty-five centimeters long.”,“Twenty-five is bigger than eight,” says Sam. “Your doll is bigger than my car.” Jenny nods. “Lets measure our towers fairly, so we can really see who won!”,Jennys tower is fifty centimeters tall. Sams tower is thirty-two centimeters tall. “You w
15、in,” Sam says. He and Jenny shake hands. “Thanks for helping us, Kevin,” Jenny says. “Youre welcome,” Kevin says. He walks upstairs.,Jenny turns to Sam. “Kevin left his ruler here. Do you want to measure more things?” “Yeah!” Sam agrees. “Race you to the kitchen!”,Your Turn!,Jenny and Sam are going
16、to measure things in their houses. You can do that, too! All you need is some measuring tape or a ruler. Remember to start at zero. You can keep track of your measurements here. Be sure to include the unit of measurement you used.ITEM MEASUREMENT _ _ _ _ _ _ _ _,Glossary,Measure: to find the exact s
17、ize or amount of something Ruler: a tool used to measure small things using standard units of measurement Standard unit of measurement: ways to measure things that are always the same Metric system: one organized collection of standard units of measurement based on the number 10 Centimeter: one unit
18、 in the metric system which is used to measure small things,More Fun with Measurement,BOOKSLeedy, Loreen. Measuring Penny. Henry Holt and Company, 1997. Pluckrose, Henry. Knowabout: Length. Franklin Watts, 1988. Roy, Jennifer Rozines and Roy, Gregory. Math All Around: Measuring at Home. Marshall Cavendish Benchmark, 2007.,WEBSITES* Teddy Bear Measurement Game: http:/www.apples4the Which Metric Unit of Length is Appropriate? http:/ an adult to help you use the Internet.,
