The palms of our hands are populated with millions of bacteria. One quick touch of an unwashed hand on a special plate is all that is needed to show this. Every day our hands come into contact with millions of microorganisms called bacteria. With plenty to feed on and some warmth, the bacteria will grow and can actually be seen. In the microscopic world of bacteria, they double their number every twenty minutes! Fortunately most bacteria die. Heat kills them and cold stops them multiplying. We wash our hands because some bacteria can make us very ill. Clean hands mean fewer bacteria on our food.

This clip is from:
Science Clips, Micro Organisms
First broadcast:
11 October 2007

This is useful for part of an activity where, under supervision, children could grow their own bacteria on agar jelly as shown within the clip. The children can then compare the amount of bacteria on their agar jelly. It is important to ensure the agar jelly is covered in a petri dish and disposed of correctly. This could lead to an activity where one child covers their hands in cooking oil to represent germs. They can then shake hands with their peers, showing how germs are transferred. Washing their hands afterwards with just water will show that this does not remove all the oil (germs) and so soap is needed. The clip would also be Useful within a PSHE lesson on personal hygiene and the importance of hand washing. This clip also lends itself to a Maths activity where the children could calculate the number of bacteria after certain amounts of time.