Points, Lines, and Planes Pacing:
This lesson should take approximately three class periods. Goal: This lesson introduces students to the basic principles of geometry. Students will become familiar with three primary undefined geometric terms and how these terms are used to define other geometric vocabulary.
Finally, students are introduced to the concept of dimensions. Study Skills Tips! Start your students off on the correct foot – vocabulary is a necessity in geometry success! Devote five minutes of each class period to creating flash cards of the major terminology of this text. Use personal whiteboards to perform quick vocabulary checks. Or, better yet, visit Discovery School’s puzzle maker and make your own word searches and crosswords (http://puzzlemaker.discoveryeducation.com/)! Language Arts Connection! To give an example of why some words are undefined, use the concept of circularity.
Students use a dictionary, either electronic or paper (yes, they are still printed!) to complete this activity. Ask students to look up the word point in their reference. Find a key word in that definition. Students should continue this process until the word point is found. Repeat this process for line and plane.
The rationale behind this activity is for students to see there is no one way to define these geometric terms, thus allowing them to be undefined but recognizable. Real World Connection!
Have students identify real-life examples of points, lines, planes in the classroom, as well as sets of collinear and coplanar. For example, points could be chairs, lines could be the intersection of the ceiling and wall, and the floor is a great model of a plane.
If your chairs are four-legged, this is a fantastic example of why 3 points determine a plane, not four. Four legged chairs tend to wobble, while 3−legged stools remain stable.
