Simple objects are scaled up in size and used to illustrate just how tiny bacteria can be. An ordinary needle has been scaled up 5,000 times. The giant needle is now 250 metres long! This comparison is used with bacteria. The viewer is asked to think how big a single bacterial cell would be if it was also scaled up 5,000 times. Would it be the size of a beach ball, a football, a golf ball or a garden pea? It would be the size of a pea. Bacteria are just one group of microbes. If algae were scaled up 5,000 times they would be the size of a golf ball, while another single-celled organism, called an amoeba, would be the size of a beach ball.

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

When introducing microorganisms, this clip will help children to understand how small they are. Pupils can create posters encouraging children to wash their hands reminding children that even if their hands look clean, they still need to wash them as they are unable to see the microorganisms that might be on them. Children may draw tables to compare bacteria, viruses and fungi, identifying their size, their features and the illnesses they may cause.