Update on Homemade Petri Dish Experiment

Ok, so, we are kind of bummed. In order for bacteria to grow, the petri dishes must be in a warm environment but that is causing them to "melt". So far, nothing is growing which isn't really unusual I guess since it can take 48 hours or more. Looking at the "before" swab last night, we thought we saw an area that looked promising. Just hoping it will hurry up and grow before the entire thing liquefies and ruins our experiment.

If you know of a good site with recipes for petri dishes, please share! We used unflavored gelatin, sugar, water, and beef bouillon in ours.

If this first experiment fails, we do have about 10 more petri dishes in the fridge. Looks like it might be back to the drawing board though.


Kim said...

did you try using the petri dishes with the toothbrush, then using a swab of like a public bathroom doorknob? I read in a earlier blog that you were using a toothbrush..maybe if nothing grows its not full of bacteria? im at loss, I've always had petri dishes that came from a science lab to do those experiments..ill research and see what I can come up with.

My So Called Homeschool Life said...

Well, we swabbed the toothbrush because I am reviewing a Violight toothbrush sanitizer which is supposed to remove 99.9% of bacteria. So, we swabbed it prior to sanitizing it and then again after the 10 minute process to see if it actually worked. I may have to buy some actual petri dishes. We had to throw the "before" swab away because it melted. It's a shame because the "after" actually started growing some bacteria but since we had to throw the before sample away, we can't compare them. The kids were really looking forward to looking at gross stuff under the microscope. LOL