Teaching a microbiology lesson

This year McMurry teamed up with the Abilene Independent School District to establish a magnet program in science and math for 5th graders.  Throughout this year, these 22 students, representing AISD geographically, ethnically, and socioeconomically, have met in a special classroom on the McMurry campus.  Their year has included all of the expectations of a regular 5th grade classroom, while also paticipating an abundance of enrichment opportunities.

This week they were involved in two.  With TAKS testing over, they are able to do some of the more eclectic activities dreamed up for them.  Afternoons have included swimming lessons from the McMurry Swim Team, while I have been teaching them some microbiology in the mornings.

We started on Wednesday by setting up an experiment to explore air quality on campus.  Students tested various locales in three buildings and also outside air for the presence of bacteria and fungi.  I provided nutrient agar plates consisting of phenol red sucrose agar and some basic instructions on how to do their sampling – find a nice flat surface in the location they desired, then open four plates, two for one minute and two for five minutes.  We checked the results on Friday and they are going to pool their data and create a 27″x42″ research poster to put on display outside their classroom in Old Main.

On Thursday, we decided to answer the question – which mouthwash REALLY works best against mouth bacteria?  Students swabbed their teeth and gums and cheeks to make lawns of bacteria on the same phenol red sucrose agar plates.  We then dipped sterile filter paper disks into four mouthwashes and saltwater to see whether any had antimicrobial activity.  We’ll check those results on Monday – which coincidentally is the day they begin canoe races in the McMurry pool.  It will be hard to top that!

On Friday, we took a cheek swab of their teacher, Mrs. Bammell, and stained the cheek cells to see if TEACHERS have bacteria in THEIR mouths.  They gave a collective “ooooh!” when I pointed out the abundance of bacteria on one of her epithelial cells.  We also conducted an epidemiology exercise by “exchanging gum”, metaphorically.  Students were given tubes of a clear fluid and transfer pipettes and asked to exchange a squirt of their fluid with no fewer than two nor more than four others in the classroom.  They worked in pairs with one person doing the exchange and the other being the epidemiologist taking notes on who exchanged with whom.  We then tested the pH of the fluid (one of the tubes had NaOH in it) and were able to find out “who got sick” and who didn’t, based on pH changes.  Then, they had to analyze the exchange patterns and determine who the original “sick” person was.  It is a pretty complicated thought process that goes into it when you have over 20 random exchanges taking place, with the order of exchanges being a clue central to the explanation.  They figured it all out in about five minutes.  No wonder the show is called “Are You Smarter Than a Fifth Grader?”

So what have they enjoyed the most?  I think it is probably putting on the lab coats and recognizing that they could set up and conduct experiments, record the results, and analyze their meaning.  Mrs. Bammell watched one young lady walk back to her lab bench with her labcoat and heard her say, “Now I FEEL like a scientist!”  They are a clever bunch, full of life, and fun to be around.  I will dissect fetal pigs with them this summer during a week-long follow-up camp we have planned.  Can’t wait!