# Logarithms Lesson 4

### Interpreting a Logarithm as an Elapsed Time

The students figure out that there is another interpretation for logarithms in the moldy pizza context. They describe logarithms as the number of hours it takes for the mold to increase by a certain factor.

##### Episode 1: Making Sense

Josh and Arobindo continue to investigate the growth of mold on a pizza. They use a number line to estimate how long it will take for the mold to increase by a factor of 10.

##### Episode 2: 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 3: Repeating Your Reasoning

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 1.5.

##### Episode 4: Reflecting

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 1,000,000.