I have devised a method with which a molecular size standard can be readily manufactured using Lambda DNA and PCR. This method allows the production of specific sized DNA fragments and is easily performed in a standard molecular biology laboratory. The material required to create these markers can also be used to provide a highly robust and reliable introduction of students to the PCR technique. Protocols for demonstrating the effect of the effect of amplification cycles and DNA and Primer concentration are provided. (Contains 1 table and 1 figure.)