# Logarithms Lesson 4 Episode 2 (Teachers)

### Exploring

The students use their number line and a calculator to determine the amount of time it takes for the mold on the pizza to increase by a factor of 10.

### Episode Supports

Focus Questions

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

1. [Pause the video at 1:15] Use the equation 3x  = 10 and a guess-and-check method (or any method you prefer) to find a close approximation for the amount of time needed for the number of grams of mold to increase by a factor of 10.
2. [Pause the video at 3:10] For the equation 32.1 = 10, state what each number means in the context of the moldy pizza.
3. [Pause the video at 5:31] Do you agree with Arobindo that from Hour 1 to Hour 3.1, the number of grams of mold increases by a factor of 10? Why or why not?

Supporting Dialogue

After watching the video, display the following: log332 ≈ 3.1546. Ask students to talk with a partner to determine what they can learn about the mold on the pizza from this relationship. Ask them to rewrite the relationship as an exponential equation.