|MadSci Network: Microbiology|
Hey, I used to live in Hingham!
To answer your question, one solution will involve using a lamp in which plates can be placed under the light bulb. A desk lamp with a long adjustable arm would be ideal. Turn the lamp on for a while with a thermometer on a surface about a foot or two below the bulb. Check temperature after 20-30 minutes. Raise lamp up or down, waiting for the thermometer reading to stabilize after each change, until the desired temperature is reached.
Other possibilities include just surveying the house to see if there are any warmish spots; the top of a computer monitor, for instance. Use a common indoor/outdoor thermometer to check the temp. Do not let the agar dishes reach a much more that 100 degrees F or you may kill the bacteria. On the other hand, bacteria will grow at lower temps than body temp, they just grow more slowly.
Moderator's Note: It's useful to keep the Petrie plates in a container when incubating the plates, particularly if you don't know what kinds of bacteria you will be isolating. (You don't want to get Bad Bugs everywhere..) Be certain to clean the area with a dilute solution of chlorox (~1%) after your experiments to kill any bugs that may have contaminated the area.
Try the links in the MadSci Library for more information on Microbiology.