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Lab: Microorganisms in the School Environment

How clean is your school??

We have just completed some bacteria labs in our Biology 1 classes.  The first lab we did is called "Microorganisms in the School Environment".  The students really like this one.  Each student is given a sterile Petri dish of nutrient agar and allowed to choose a location in the school.  The purpose of the activity is to determine where in the school the most bacteria are found.  Students take a sterile swab and rub along surfaces in their location, then streak their swab across the surface of their agar.  Dishes are incubated for 48 hours, and the total number of colonies are counted.  

Students are often amazed at the results.  The students are always convinced that the cafeteria and the bathrooms will be overrun with bacteria, but the results usually show that these locations have the fewest bacteria.  Almost always, we find that a locker has the highest number of bacteria!

I don't place a lot of validity on the test results, but it is a fun activity to do when teaching a unit on microorganisms.   Just remember to have the students seal their dishes with tape, and do not allow the dishes to be opened after the bacterial colonies have grown.

Here is the link to my lab on as well as links to some related products.

Lab:  Microorganisms in the School 

Viruses and Bacteria Complete Unit Plan

Bacteria Homework / Study Guide

Happy Teaching!!


  1. Awsome site! I am loving it!! Will be back later to read some more. I am taking your feeds also
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  2. We should keep our school environment clean and healthy an it is very useful to the children need get good satisfaction to all and everyone in the school.
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