# Logarithms Lesson 3 Episode 4 (Teachers)

### Reflecting

Josh and Arobindo find out what a logarithm is. They describe how to use logarithms to find the time when the pizza had any given number of grams of mold.

### Episode Supports

Focus Questions

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

1. [Pause the video at 0:46] What does the logarithm notation mean? For each logarithmic equation shown, can you write an equivalent expression using exponents instead of logarithms?
2. [Pause the video at 1:42] Write a logarithmic expression that gives the hour at which the pizza has 65 grams of mold.
3. [Pause the video at 3:02] Examine the logarithmic equation log3200 = 4.823. What does this equation tell you about the moldy pizza?

Supporting Dialogue

After watching the video, ask your students to tell each other what logarithms are. Ask them to discuss why we might use logarithmic notation instead of exponential notation. Ask them if they have ideas for how to find logarithms.