The document announces that Test 2 will take place on March 22nd, 2011 at 8pm in the big Hall, and Test 4 will take place on April 5th, 2011 at 8pm in the big Hall. It then discusses serial dilution, noting that plates with too much or not enough growth are hard to count colonies from, but plates with definite single colonies allow for the best estimate of CFU. It asks the reader if they got an answer of 5.6 x 108 CFU/ml for a calculation involving serial dilution.

1. AnnouncementNext test (Test 2) is on March 22nd, 2011 Tuesday at the big Hall 8pmTest 4 is on April 5th, 2011 Tuesday at the big Hall 8pm

2. Serial DilutionPay attention as I’m going to Quiz you on thisTODAY

3. Serial Dilution

4. Too much growth, hard to count coloniesGrowth not as much, but still hard to count coloniesOK to count but there are some colonies that are not single colonies, they are so close togetherDefinitely the best plate to estimate the CFU

5. Serial Dilution cont’d

6. Try this!!!!!

7. Did you get 5.6 x 108???

12. 5.6 x 108 CFU/ml