CMS Lesson # 7 Making and Using a Ruler

1. CMS Lesson # 7Making and Using a Ruler Objectives: - I can measure objects to the nearest half and quarter inch.

2. Review • Compare the following fractions using <, >, =: 2/3 3/4 • What is 2/3 of 21?

3. Pass out “inch bricks” (inch graph paper) to students. • Last lesson, we measured how far we could jump using a dinosaur fossil. Today, we are going to measure items using this ‘inch brick”. Find some things that are about ½ inch long/tall etc. Mark the ½ inch point using a blue or black pen. • Next, mark ¼ inch on your brick in red pen. How do you know that’s ¼? Are there any other fourths? Mark the remaining fourths.

4. Although we often measure things to the nearest half or quarter inch, we don’t often find things to measure that are less than an inch. How can that be? Allow students time to discuss. • You are going to make a ruler with a partner using inch bricks. Who knows how many inches are in a foot? How many inch bricks will we need? • Allow partners time to make their rulers. You will need to mark the half and quarter inches (it will be easier for students to see if they use a blue/black pen for halves and red for fourths). • You will measure items around the room. See next slide for your recording sheet.

6. Hand out a traditional ruler and give partners time to compare the ruler they made with a standard ruler. • What do you notice? • What do the shortest marks between whole numbers mean on the standard ruler? What do the longest marks mean? • Measure a few small items in your desk with your ruler, and then with the standard ruler. • Which ruler is easier to use? Why? Which is more accurate?