Students pass a contagion, Serratia marcescens (non-pathogenic, opportunistic bacteria that forms bright red bacterial colonies), through a series of recorded handshakes. The gloves used in the handshakes are swabbed after the first 2 handshakes and after the fourth. ANy errors in procedure can be discussed with reference to problems in reposting in actual epidemiological studies. I first created this lab while teaching a non-science major course in Microbiology at San Diego State University in 1972.
This is an excellent laboratory for developing critical thinking skills.