# Scavenger Hunt for Lengths

#### 1 Hook

Begin the lesson by briefly reviewing measuring and estimating length. Direct students attention to a long object in the classroom. Ask students to suggest different ways to estimate its length. Possible strategies include estimating the length of part of the object and using this to estimate the whole length, comparing the length with a length they know, and estimating the shortest and the longest possible lengths and using these to estimate the range of the length.

#### 2 Direct Instruction

Have two students measure the object. What unit should they use to measure it? Why, for example, would you use feet, not inches, to measure the length of a chalkboard? If students need additional practice, have them select a few more objects to estimate and measure. Emphasize that estimates are approximate, not exact, measurements. Group students into teams of four. Provide students with measuring tools, such as rulers, yardsticks, tape measures, and trundle wheels. Students may also make their own yardsticks by cutting a piece of string 1 yard long, marking feet in one color on the string, and marking inches in a second color over the length of 1 foot at one end of the string. Distribute the Classroom Activity Sheet: Measurement Scavenger Hunt to each student. Have students work in teams to answer all the questions on the sheet. Each student, however, should fill in his or her own sheet. Students should try to finish the sheet during one class period. As you observe students measuring in class, encourage them to estimate to help them find appropriate objects.

#### 3 Guided Practice

At the beginning of the next class, go over the answers to the questions on the Classroom Activity Sheet. Discuss with the class when it is useful to estimate and when it is important to know the exact measurement. For example, if you were trying to determine whether a chair would fit through a doorway, an estimate would probably be sufficient.But if you were cutting lumber for a house you were building, you would need to know exactly how long to cut the pieces.

#### 4 Independent Practice

Distribute the Take-Home Activity Sheet: Measurement Puzzles for students to work on over a couple of days. If possible, devote a few minutes to a discussion of students strategies and solutions once they have completed the sheet. Another strategy involving the same material and concepts might involve having students work in groups of two or three to choose a starting place and a secret destination. Possibilities include the door of the classroom, a certain tree in the schoolyard, a mark on the gym floor, and a gate in the schoolyard. Ask each group to make a map from the starting point to the destination that shows measurements, including inches, feet, and yards. Arrange for groups to trade maps to see whether the other groups can find their way to the secret destinations.

#### 5 Wrap-Up

I would finish the lesson by asking my students to hypothesize about the possibility of developing a new standard unit for measuring length. Plan the unit. Explain whether the unit would be shorter than 1 inch, between 1 inch and 1 foot, between 1 foot and 1 yard, between 1 yard and 1 mile, or longer than 1 mile. Express the unit in terms of inches, feet, yards, or miles. Debate the advantages of the new unit. I would tell them this is what we will discuss next class so be prepared!