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Decimal Numbers vs Scientific Notation
Decimal numbers can be converted to scientific notations by moving the decimal place the same number of
places as the exponential number.
100.0 = 1.0 x 102 1. 0 0 = 100
350.0 = 3.5 x 102 3. 5 0 = 350
Microbiologics Dilutions Guide
This document outlines how to perform dilutions when using Microbiologics products. Dilution is the process
of making a solution weaker or less concentrated. In microbiology, serial dilutions (log dilutions) are used to
decrease a bacterial concentration to a required concentration for a specific test method, or to a concentration
which is easier to count when plated to an agar plate. This document was created to provide a better
understanding of dilutions and should be used as a guideline, not a replacement for laboratory procedures.
Log Dilutions
A log dilution is a tenfold dilution, meaning the concentration
is decreased by a multiple of ten. To complete a tenfold
dilution, the ratio must be 1:10. The 1 represents the amount
of sample added. The 10 represents the total size of the final
sample. For example, a sample size of 1 ml is added to 9 ml of
diluent to equal a total of 10 ml.
Example: 1:10 dilution - if the concentration is 1,000 CFU, a one log
dilution will drop the concentration to 100 CFU.
Initial sample
1.0 x 103
(1,000 CFU/ml)
1 ml
9 ml dilution tube
9 ml + 1 ml = 10 ml
1.0 x 102
(100 CFU/ml)
Decimal Number 1 10 100 1,000 10,000 100,000 1,000,000
Scientific Notation 100101102103104105106
