Bacteria can be cultured from dirty fingers and other places, and this might be a good way of discussing hygiene-related issues. Handwashing with antiseptic solutions is an attractive starting point for simple experiments, but the results are not always easy to interprete. Many of our skin bacteria are in for the long haul - they are well adapted to their ecological niche and simple handwashing may not be enough to remove them. It is important to show that handwashing is important - it reduces the level of gross soiling, decreases the total microbial load and is very effective against transmission of particularly harmful organisms. Another experiment which can involve culture techniques is the artificial epidemic.
Students shake hands at random whilst wearing gloves.
One of the gloves is seeded with a bacterium recognizable after culture of swabs taken from the gloves. We trialled this experiment at the Investigator Centre with some success using fluorescent dyes instead of bacteria. You could also consider microbes as recyclers. This is an interesting theoretical project, but with the potential for practical exercises that should not cost much. However keep in mind the well publicized risks of handling some composts.