Grade Level: 4, 5, 6

Subject(s):

• Mathematics/Geometry

Duration: 45 minutes

Description: This lesson describes a hands-on way for students to learn about  lines, rays, segments, and points. Students use yarn to create a "web" of parallel and perpendicular lines.

Goals: Students will realize that lines, segments, rays, and points exist not only on paper but in the world around us.

Objectives:

1. Students will be able to identify, describe, and compare line segments, lines, rays, and angles and use appropriate symbols.
2. Students will communicate mathematical understanding in journals using words and/or pictures, numbers, and symbols.
3. Students will construct meaning through physical materials.
4. Students will express ideas using mathematical vocabulary.

Materials:

• yarn
• wipe boards/dry erase makers for students
• letters of the alphabet cut out of construction paper; attach black dots to the letters to represent points (laminating works well)

1. Ray - A line starting at a single point and going on forever in one direction.
2. Point - A fixed spot on a plane.
3. Line - A straight line going on forever in both directions.
4. Segment - A line with two endpoints.
5. Parallel - Two lines, line segments, or rays that are constantly equidistant apart from one another so that they never intersect.
6. Perpendicular - A line, line segment, or ray that touches or intersects another line, line segment, or ray at a 90 degree angle.
7. Intersecting - Two lines, line segments, or rays that touch or pass through one another at any angle.

Each student sits near the web with a wipe board. Ask students to find (one at a time) rays, points, lines, segments, intersecting lines, parallel lines, and perpendicular lines. Students must re-draw each figure on their wipe board, label it correctly, and write the symbolic form. Students use the alphabet points that were placed at intersecting points on the web to label the lines, rays, etc. that they find. Then students write out the figures that they find using the correct form of mathematical labeling. [I also had my students write how they would say it out loud when naming it. Example: "Line AB or line segment AB is perpendicular to line segment CD."] Below is information on how students should label rays, lines, etc.

1. Ray - The endpoint letter first, then a second point with a line ending in an arrow over the two letters, pointing to the right.
2. Point - A dot and then the point's letter.
3. Line - Two points on the line with a line with arrows in both directions above the letters.
4. Segment - The two endpoint letters of the segment with a line, no arrows, above the two letters
5. Intersecting - (AB x BC) The AB and BC would have a line or a line with arrows above them to show what figures they were. The x stands for intersects.
6. Parallel - (AB // BC) The AB and BC would have a line or a line with arrows above them to show what figures they were. The // stands for parallel.
7. Perpendicular - (AB _|_ BC) The AB and BC would have a line or a line with arrows above them to show what figures they were. The _|_ means perpendicular.