how can you test the amount of bacteria in water?

Question

I am doing a science fair project on the amount of bacteria growth in different temperatures. does anyone know how to do the procedures?

Answer 1

a pH test you can get them at walmart in the pool isle and can cost about 40 bucks

Answer 2

What you can do is take a small amount of water and spread it over a petri-plate with media on it that promotes the growth of bacteria. You grow each plate the same amount of time and compare the different temperatures. The plate with more colonies has a higher concentration of bacteria. It is important that the volume you use per plate is exact though, so that you are doing a proper comparison.

Edit to say that media for growing bacteria usually contains yeast extract and some type of "Broth" recipe. In order to make these plates effectively, you also need an autoclave, so you really would need the help of at least a science teacher at a high school to get these plates. Alternatively, you can contact a university professor and likely get one to just give you the petri plates you would need to conduct the study. OR you might even be able to order or find pre-sterilized pre-made petri plates with agar already in them from a science supply store. Good luck!

Answer 3

I read above that you use media, um call me a dumb blonde, but what is that and where can you get it? and how long does it take for the bacteria to grow?