Getting Started with Agar

     As most of my experiments involve taking bacterial samples from everyday objects that we encounter, I have chosen to use a very neutral nutrient agar for bacterial growth. Nutrient agar is a great agar that is basically used as a bacteria "food", allowing bacteria to grow in a controlled environment. In this case, I will be taking samples of bacteria from everyday objects and placing them in petri dishes with the nutrient agar in them.

     I chose to purchase agar that I would heat and portion into empty petri dishes myself, rather than buying pre-poured agar dishes. I purchased my nutrient agar, petri dishes, inoculating needles, and sterilized swabs from Home Science Tools. The first step to getting agar plates ready is to melt the nutrient agar and pour them into the petri dishes, as shown below:

Nutrient agar is to be heated at 200 degrees Fahrenheit for approximately 1 hour, until it is pourable and completely liquid. Once heated, the agar is poured directly into the petri dish by opening the dish's lid just enough to pour the agar, in order to avoid contamination. There must be enough agar to completely cover the bottom of the petri dish. Here, I have heated enough agar to create a total of 9 petri dishes:

Once the agar is poured into the petri dishes, they must be allow to sit at room temperature for about 1 hour, until the liquid settles back into a gel. Once settled, the dishes must be refrigerated until use.

     After taking a bacterial sample with a sterilized swab, bacteria must be incubated at about 97 degrees Fahrenheit for 2 days, or room temperature for 3 days. Using a large plastic Tupperware dish (with lid), a heat lamp, and a temperature gauge (originally from my reptile kit), I designed a well-controlled environment were I can safely monitor, grow, and observe my bacterial samples:

     Now that my home laboratory is set-up, I can begin taking samples of everyday objects and allow the bacteria found on those objects to grow.