(See related pages)
|
|
|
10.1 TeachingTeachers should provide many hands-on opportunities for students to choose [measurement] tools . . . Although for many measurement tasks students will use nonstandard units, it is appropriate for them to experiment with and use standard measures such as centimeters and meters and inches and feet by the end of grade 2. NCTM Standards 2000, page 105Write a measuring activity for school students to introduce length with nonstandard units. Select two nonstandard units of measure and choose several common classroom objects to be measured. Write a question that enables students to understand why an agreement on standard units is important. Write several questions that might be asked to help students see that a measurement depends on the size of the unit and the number of times the unit is marked or measured off. Also write a question to help students see that the measurement obtained from a unit of measure increases as the size of the unit decreases. 10.1 Concepts In the middle grades students should also develop an understanding of precision and measurement error. By examining and discussing how objects are measured and how the results are expressed, teachers can help their students to understand that a measurement is precise only to one-half of the smallest unit used in the measurement. NCTM Standards 2000, page 243To introduce students to the idea of precision, one teacher used cardboard strips to form three types of rulers: one marked off only in inches; one marked off in inches and half inches; and one marked off in inches and quarter inches. Write some examples involving the use of these rulers and describe how the idea of precision can be illustrated. Write a summary statement about precision and the size of the unit being used. 10.1 Concepts One advantage of the metric system of measurement over the English system is the relationship between units of volume and cubic units. For example, if an object is submerged and displaces 270 milliliters of water, what is its volume in cubic centimeters? If an object is submerged and displaces 6 cups of water, what is its volume to the nearest tenth of a cubic inch? To continue the comparison between the metric and English systems, what is the approximate mass of one cubic centimeter of water, and what is the approximate weight in ounces of one cubic inch of water, if one pint of water weighs about one pound? Write a summary statement comparing some of the other advantages of the metric system to the English system of measurement. |