Soil Bacteria and Controls and Variables

Today we talked about what it means to have a controlled experiment and set up our own lab to culture soil bacteria. Over the next few days, we should have agar plates that resemble the one below.After setting up our experiment, we used the Simpsons to practice identifying controls and variables in experiments.

Homework: finish the back of the Simpsons controls and variables worksheet. Note: These two problems are harder than the three on the front of the worksheet. Just try your best. You can do it!

Here's a math hint for the Krusty the Clown problem:
50% (or half of 30) =15
So... if the new itching power is advertised to last for 50% longer that the original itching powder (which lasts 30 minutes), the new itching powder lasts for 45 minutes, then the advertisement is correct.