Expert: Walter Hintz - 9/24/2005

Question
I am in grade 6. I am interested in doing a project on who's mouth is cleaner mine or my dogs. I already read your email to Aubrea. Where can I find more information on this? And once I get growth will you help me along, I'm sure I'll have more questions. Thanks    P.s. If I want to get agar plates where do I go? Thanks again

Answer
Hi Liz:
I don't remember what or when I gave advice to Aubrea but I would be glad to help you.  The first think you have to do is make a plan: state your problem, make a hypothesis and then design your experiment.  You will not be able to use the term cleaner mouth in the problem.  Your problem should be . Which mouth has more bacteria:  My dog's or mine?  Now the hypothesis:  You make a quess to answer this question such as
   A dog's mouth has more bacteria than a human mouth. Or you can reverse the hypothesis.  It makes no difference.  Make your best guess
  To design your experiment you will have to grow bacteria.  This is not easy and you must be very careful when you do it. Here is what you will have to do
1. Yes you will need bacteria plates.  Do you have a high school biology lab where you might beg for some?  Better yet is there a college nearby?  If so go to that biology dept. and ask for some.  They can only say no.  Smile when you ask and bat your eyes at them when you ask. My younger used this method whenever she wanted something.  Get about half a dozen.
   If you can't beg them or your school cannot buy you some you will have to make your own..  You will need unflavored gelatin and powdered beef boullion.  Experiment a little to get it right. mix the beef broth in a small amount of water and boil it and add the geletin and let it set. you need some kin of a flat dish.  Try to get some petri dishes or use some plastic container lids. Rinse them in boiling water.
Once you get the media let me know and I will tell you what to do next.  From now on use my email address only. It is
  waltjh@sbcglobal.net
Title it "School help" or my spam blocker will toss it is the trash.