Question 14 asks students to answer a question similar to Yolanda's in the beginning of the lesson.
Summarize the investigation by asking:
- If you know the number of identical objects, how can you find the total mass? Show us your strategy and give examples.
Try to select a variety of students who can show different solution strategies that include the use of words, pictures, data tables, and graphs.
Direct students' attention to the Luis and Michael's Pencils section of the Mass vs. Number pages in the Student Guide. Assign Question 7 of this section. It introduces data in which the objects are clearly not identical in mass. To identify the data table and graph for this data correctly, students use knowledge gained in this investigation about the patterns of nearly identical data.
- How did you determine which graph was Luis's and which was Michael's? (Possible response: Michael's pencils were identical so the data points on his graph fell in a straight line. Luis's pencils were different sizes and shapes so the data points on his graph fell in a more crooked pattern.)
- How is getting data points in a straight line connected to having a collection of nearly identical objects? (For each object, the mass increases at a regular amount, so the data points make a regular pattern. If the objects were not identical, the data points would not fall in a straight line.)
- Think about Yolanda's oat bran bars. If they were all different sizes and weights, would she be able to use a best-fit line to find the mass for any number of bars? Why or why not? (No, because the data points would not make a regular pattern and fall in a straight line.)
- If Yolanda wants to find the mass for any number of bars, which is the best tool for her to use, her data table or her graph? Why? (Yolanda's point graph has a best-fit line that would enable to her to easily predict the mass of almost any number of bars. Her data table only records the mass of 1, 2, 4, and 8 bars.)
- Which tool do you like best to find patterns in data? Why?
