measuring bacteria growth--please help me!

<p>Serratia marcescens colonies are TONS of red little pigments after cultivated on a petri plate. Then how am I to "measure" its growth? It doesn't seem like I can count the bacterial colonies? Or could I? Any informationwill be highly appreciated! Thanks!</p>

<p>i did this bacteria growth lab in my biology class a couple years ago. we drew a grid on the petri plate, then we'd put the plate on a lighted overhead, draw a matching grid on a piece of tracing paper, then shade areas that had bacteria growth. After that, we'd estimate the total area of bacteria.</p>

<p><a href="http://www.newton.dep.anl.gov/askasci/mole00/mole00353.htm%5B/url%5D"&gt;http://www.newton.dep.anl.gov/askasci/mole00/mole00353.htm&lt;/a&gt;&lt;/p>

<p>try this.. hope it helps</p>

<p>I did an experiment in 9th grade for the local science fair about how temperature affects bacterial growth for various species. To measure them, we first took pictures daily using a computer-camera thing, and then when we got them on the computer, we used this one software program (called DaVinci which my partner's dad developed/helped develop but is still public domain since he did it with public funding) that basically counted all pixels with RGB values above a certain amount, and we got really close to the area of the bacterial colony with this. We had to of course assume that the "number" of bacteria is directly proportional to the area of the colony though.</p>