Cambridge Secondary (7-9). Stage 7. Science. Learner's Book - Unit 7: Microorganisms in the environment - Question 5

Safety adaptation: This is an observation-only version of the book’s classroom practical. The source activity grows microorganisms from the air on sterile agar in a sterile Petri dish, then keeps the lid fastened and observes the closed dish. It lists safety glasses, tape and a plastic-writing pen, and warns not to breathe or talk over the agar and not to remove the lid after closure. The source also describes turning the dish upside down to keep condensation off the agar, labelling it with a name and date, and observing it after a few days. Those culture-setup steps are replaced here by observation of an already prepared resource. Do not carry out environmental culturing at home. Use teacher-provided photographs or a prepared closed specimen under the teacher’s safety rules. Do not open, touch, smell or taste the contents; leave handling and disposal to trained staff.

Observe the teacher-provided photograph or prepared closed specimen. Record the visible shapes, sizes, colours and positions of any colonies. If no colonies are visible, record that instead.