![]() This means that the dilution factor is 1:10 in each step and that from one sample you take 1 part of sample solution to 9 parts of culture medium (or another suitable liquid) in a test tube, mix and transfer 1 part of mixture to 9 parts of culture medium in a new test tube and so on until a suitable degree of dilution has been reached. The most common is to make a 10-step dilution series to achieve high accuracy at large dilutions. In microbiology, one often wants to make dilution series when deciding how many microorganisms there are in a sample. Log 10 (1/1000) = -3, since log 10 (1/1000) = 0-3 = -3ġ0 0 = 1 (can not really be explained mathematically, but has for practical reasons been defined as 1) ) It follows from the second rule that log 10 (1 / b) = 0-log 10b = -log 10b the following expressions apply for all types of logarithms: Lg 1000 = 3 because 1000 = 10x10x10, which can also be written 10 3.Īccording to the logarithm rules, e.g. For the sake of simplicity, only log or lg is often written or said, when referring to the base-10 logarithm. The number b is called the base in the logarithmic system you want to use and most common in science and engineering is that you use the number 10 as a base and then you talk about base-10, decimal or common logarithms, which are usually written log 10 or lg 10. ![]() The logarithm (log) of a certain number (x) is the number (y) to which another number (b) must be raised, to give the number x. When discussing the number of microorganisms in cultures from for instance food samples or when preparing and describing dilutions, logarithms are most often used to express the dilution factor.
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |