The students explore the definition of a logarithm and describe a logarithm as an exponent in an exponential expression. They interpret logarithms in a moldy pizza context as the time at which a slice has a certain amount of mold.
Josh and Arobindo create a number line to model the growth of mold on a pizza slice. They estimate when the pizza will have 50 grams of mold, and mark this in on their number line.
The students use their number line and a calculator to determine when the pizza slice had 50 grams of mold with more precision.
Arobindo and Josh use their number line and a calculator to determine when the pizza slice had 110 grams of mold.
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.