A) WHAT IS THE PROBLEM WITH HER PLAN?
Binary fission is one of the asexual process by which most bacteria reproduce, the binary fission brings about a doubling of the number in bacterial cells that are viable.
Generation time is that time that it will require for a cell population to divide and double, it is also known as doubling time. This Generation time varies among distinct organisms and also varies among culture conditions.
Take for instance,a fast growing bacterium that is under an ideal culture conditions has a doubling time of 20minutes and for the bacteria that is grown in a condition that is not so ideal,may have a doubling time of hours.
The major challenge/ problem with her plan is that as she takes the bacterial sample every 30minutes, and then hold the sample till the last sampling is done in the day,those bacterial cells that are collected in the initial intervals will then get divided and further gives a result that is false.
However,if those bacteria that are collected aren't stored in a culture environment that is standard,the bacterial cells may die off and thus will further bring about a false result.
2) CAN SHE DO ANYTHING TO IMPROVE THE ACCURACY OF HER RESULT?
Solution for rectifying the error in her plan;
She can go ahead and add 50-100 μl of formaldehyde to all the culture suspensions that she has and has taken every 30minutes.
As the formaldehyde will fix the bacterial cells,The optical density present in all those aliquots can then be retrieved/taken at the end of the day.
Looking at it alternatively, aliquot 1ml of the culture suspension at an interval of every 30 minutes,and then take the optical density that is OD at a wavelength of 600nm making use of spectrophotometer until the reason you get becomes static.