Expert: Walter Hintz - 11/5/2008

Question
Hello Mr. Hintz,

 I'm very honored to have the chance to ask an expert a question! Well, I'm going to participate in a science fair and I chose to do " Whose mouth is cleaner a dog's or a human's?", and I'm not really sure what to do. I know that I'm supposed to do an experiment with the petri dishes and nutrition agar, but other than that I don't know what to do.Also,what exactly is a hypothesis? How do I put this all on a display? Thanks!! :)

Answer
Hi Alexandra; In the scientific method you first decide on a problem or question  You have done this. Which mouth is cleaner.  Now you state a hypothesis or educated guess.  You hypothesis here could be  "A human mouth is cleaner then a dog's mouth" or you state it the other way around if you wish.  Perhaps you might think a dog's mouth is cleaner.  
The next step is to design an experiment to test your hypothesis.  In this case you would get some media and petri dishes  and put saliva from a dog and some from a human on the dish and see what grows and compare them.  You keep good notes and data and report you results and conclusions.  You should ask your teacher about the display required.
Keep me informed as to waht you are doing and I will help you. You will need help regarding the results and you must be very careful when growing germs.  I will tell you how to handle that also.
If you want to get back to me again use my email address
waltjh@sbcglobal.net