Thursday Tool School: Measurement Tools- Clock Angles

Frame from Creative Clips by Krista Wallden

Today's activity is super simple but adds a little variety to your basic angle classification/ measurement lesson. The activity emphasizes the use of Judy Clocks, those cute little geared clocks that you don't find much use for except during your time unit. "Clock Angles" requires students to use the hands on a Judy Clock, or other geared clock, to determine the angle formed by the hands. After students have experience classifying the angles, students use protractors to measure them. 

Specifically, this activity addresses the following Common Core State Standard for Mathematics: 

• 4.G.A.1- Draw points, lines, line segments, rays, angles (right, acute, obtuse), and perpendicular and parallel lines. Identify these in two-dimensional figures.
• 4.MD.C.6- Measure angles in whole-number degrees using a protractor. Sketch angles of specified measure.

The biggest challenge students have with this activity is that they misrepresent time on the clock. For example, when asked to show 12:15, many students represent it as a right angle; however, with a geared clock, students will notice that the hour hand is just past the 12, making it an acute angle. See the example to the right. 

This activity not only emphasizes representing clock time correctly but identifying angles as well. The picture below shows the activity sheet for this lesson. In Part I, students classify the angles as either acute, right, obtuse, or straight. In Part II, students use a geared clock to represent the time and then classify the angle. 

Freebie Alert! Click here for a free download of this resource. 

To extend the activity, students can create the clock times in Part II on a blank clock face and then measure them with a protractor to verify their answers. See the picture below for an example. 

Sound Off! How else do you use Judy Clocks or other time manipulatives in the classroom? How do you teach your angle standards?