What is PCR? What is its purpose? With this great introductory activity, students will gain an in-depth understanding of the polymerase chain reaction (PCR) by performing this exciting hands-on activity. A simulated DNA molecule will be physically duplicated over and over again to allow your students to gain a better understanding of the steps involved in PCR. An excellent way to teach the important principles of PCR before students perform actual experiments. Includes an informative background, DNA and primer cutout sheets, and teacher tips and extensions.