What do these MicroOrganisms require to live ??

The 7 Characteristics !


What do we need to keep bacteria and fungi alive ?

Agar dishes


Agar or agar agar is a gelatinous substance derived from seaweed. Historically and in a modern context, it is chiefly used as an ingredient in desserts throughout Japan, but in the past century has found extensive use as a solid substrate to contain culture medium for microbiological work. The gelling agent is an unbranched polysaccharide obtained from the cell walls of some species of red algae, primarily from the genera Gelidium and Gracilaria, or seaweed(Sphaerococcus euchema). Commercially it is derived primarily from Gelidium amansii

OB65 investigate the presence of micro-organisms in air and soil


Julius Richard Petri was a German bacteriologist who is generally credited with inventing the Petri dish while working as assistant to Robert Koch


  1. Take 4 Petri dishes per group
  2. Seal one of the petri dishes without exposing it to anything
  3. open 1 dish and leave it open for 10 mins
  4. Take 1 dish, opening the lid as little as possible sprinkle some soil on the agar
  5. Take 1 dish, opening the lid as little as possible spray some water on the agar
  6. Between you all you should test a mobile phone, Keyboard, Copier button, steering wheel shoes, box of tissues using a cotton bud.
  7. close the lids on them all
  8. seal all the dishes
  9. write the conditions exposed to on the lid or the seal
  10. Leave for a week
  11. Observe and sketch results

pre- Diagram

Safety concerns

Safety concerns






Furry growths are fungal

Coloured shiny growths are bacterial colonies


The ____ dish had the most Fungal colonies

The ____ dish had the most bacterial colonies.

The Control dish had no growth as it was sterile to begin with and was not exposed to any bacteria or fungi.


If you have spare agar dishes available, you could investigate to see how infected common or shared items are. Such as

  1. Boy Vs Girl
  2. Mobile Phone
  3. Copier Button
  4. Door Handle
  5. Water font
  6. ..... any ideas ?

Or to do a quiz guesstimate .... http://theoatmeal.com/quiz/phone_germs/go