## Lesson: Measuring and Comparing Length

Developing the Concept

Once the children have had experience measuring with nonstandard units, they are ready to make the transition to measuring in inches and centimeters.

**Materials:** an inch ruler and a centimeter ruler for each child or pair of children; a plastic bag containing the following items for each child or pair of children: an unsharpened pencil, a new crayon, a felt-tipped marker, an index card, a paintbrush, a new piece of chalk, and a craft stick; a copy of the Inches and Centimeters (PDF file) worksheet for each child; several clear plastic inch and centimeter rulers for use on the overhead

**Preparation:** Collect the items listed above and assemble the bags. Make a copy of the worksheet for each child.

**Prerequisite Skills and Concepts:** Children should know how to measure using nonstandard units. They should understand how to align the edge of the nonstandard unit and the object being measured to get an accurate measurement.

**Wrap-Up and Assessment Hints**

Have children run ruler races. Give two children a number cube (1-6), an inch or centimeter ruler, two pieces of paper, and several markers or crayons. Have children take turns rolling the cube to determine the length of the line they should draw (e.g., 1cm, 2cm, 3cm, and so forth). Then have them draw a line that is that length. Each time they roll, have the children use a different color crayon to add that many inches or centimeters to their line. The first child to span the page wins. Children should work lengthwise across the paper if they are racing in inches and “widthwise” across the paper if they are racing in centimeters.