Logarithms Lesson 2 Episode 2 (Teachers)

Exploring

Josh and Arobindo explore the growth of the beanstalk between Day 5 and Day 19. They write two equivalent expressions to represent this growth and use a number line to justify their expressions.

Episode Supports

Focus Questions

For use in a classroom, pause the video and ask these questions:

1. [Pause the video at 2:12] Can you write two equivalent expressions to represent the growth of the beanstalk over a 14-day period? Use the number line created by Arobindo and Josh and the arcs they have drawn to help you.
2. [Pause the video at 2:44] What does “three to the seven, squared” mean? Why is it equivalent to 314?

Supporting Dialogue

Josh and Arobindo have discovered several equivalent expressions to describe the growth factor of the beanstalk over a 14-day period. Each expression can be interpreted differently, however. For example, 314 can be described as the growth factor over one 14-day period, while (37)2 might be described as the growth factor over two 7-day periods. Ask your students to pick two of the expressions from the video (314; 97; (37)2; and 3×37) and first, explain how to interpret each expression in the context of the beanstalk, and then explain why the two expressions are equivalent. After some time, invite pairs to share their ideas, with a goal of exploring each of these expressions as representative of the same quantity, the growth factor of the plant over 14 days.