Page 153 - IM_FL_Geometry_Print Sample

What do you notice? What do you wonder?
Student Response
Things students may notice:
• The salt seems to form ridges.
• Those ridges extend from the corners and seem to meet at a single point in the center. • Those ridges seems to bisect the angles of the triangle.
• There is a cup and a plate used to catch the salt.
Things students may wonder:
• Would these ridges appear the same if we used a di erent triangle?
• Would these ridges all meet at the same point if we used other polygons? • How tall is the pyramid of salt?
Activity Synthesis
Ask students to share the things they noticed and wondered. Record and display their responses for all to see. If possible, record the relevant reasoning on or near the image. After all responses have been recorded without commentary or editing, ask students, “Is there anything on this list that you are wondering about?” Encourage students to respectfully disagree, ask for clari cation or point out contradicting information.
Ask, “What would cause a grain of salt to fall towards one side rather than the other? What does the ridge between two sides of the triangle represent? What about the point in the center?” The main idea here is that the ridges represent the points that are the same distance away from the two sides they are between. The center point is the same distance away from all three sides. If not mentioned by students, bring up the conjecture that the ridges, when viewed from above, appear to be angle bisectors, meaning that the angle bisector is the set of points that are the same distance to each ray of the angle.
8.2 Not Falling O the Salt Pile
15 minutes
80
Teacher Guide