# Determining Relative Size: Measure Up!

The world is their measuring stick! In this lesson, students will practice measuring objects using the world around them for units of measurement.

#### Learning Objectives

At the end of this lesson, students will be able to measure objects using another object and compare the results.

#### Introduction

(5 minutes)
• Call students together. Ask them to think about times in life when people need to know what size something is. If students are having trouble coming up with answers, suggest times when they have seen adults cooking or shopping for clothing. Ask them why they think this is important to know.
• Next, ask students how people measure these objects. Students may suggest answers like measuring cups or using a ruler.
• Ask students about times when it is very important to know the exact amount of something and times when a general idea is good enough.
• Tell students that there are formal units of measurement and show them a ruler as an example. Every time someone measures something in inches, it should always be exactly the same length.
• Ask students to look at their feet. Because students’ feet are each slightly different sizes, if everyone in the class measured something with their feet, the results would not be exactly the same. However, if the same person measured the item numerous times, the measurement should be the same.
• Tell students it is possible to compare items as long as the unit of measurement is consistent. If they use the same hand, foot, pencil, etc. to measure two objects, they can determine which one is bigger or smaller.