Use the need for cleanliness during flu season to engage your students.

Does it really matter whether you kill 99.9% of the bacteria or 99.999% of the germs?

In this 3-act activity we've asked students to consider whether these claims about these two wipes' efficacy really make a difference. We've supplied students with a list of bacteria counts on various surfaces and asked them to calculate how much of a difference these two different percents make in wiping out germs.

This is an excellent opportunity to deal with repeating decimals. Thanks to Kyle Berry for sharing this image with us!