My son is in the 4th grade this year and doing a science project. We were thinking of doing the expierment where you grow bacteria from a dogs mouth, and then from a humans mouth to see which one has more bacteria in it. Anyone have any ideas, how to help make this a success. DO i need AGAR, or can i make it myself? Thanks alot to all who reply!

Agar and growing bacteria fall under the 'Modern and Theoretical Physics' forum section!?

 

Maybe if a mod moves this to a bio section it's more likely to be found by someone who can help!

Sounds like a fun project, regardless of the forum topic in which it lands.

 

Agar was my first thought. I'd be curious to hear some suggestions and how this thing turns out!

 

Btw...It'd be fun to use multiple dogs and multiple humans so you can use an average/mean, instead of single subject outputs.

 

Damn... 4th grade is getting tough!

Well you need a medium with agar with it. But two caveats: a number of mouth bacteria are potentially pathogenic. So I would not advise to use media in which they can propagate. I probably would not want to do the experiment with younger kids, actually.

 

Second: unless you brushed teeth just before sampling, the amount will not be significantly different between humans and dogs. Expect in the area of 10^9 bacteria per ml of saliva (so dilutions are necessary to count the colonies).

 

And yes, definitely wrong forum section.