In this activity, learners make balloon models of disease-causing bacteria. This activity provides a fun and hands-on way of learning about the shape and structure of bacteria and also introduces the concept of bacteria as disease-causing organisms. This activity is supported by an educator's presentation and presentation notes. Safety note: before running the activity, check whether any of the learners have latex allergies. If there are any learners with latex allergies provide alternative craft materials such as cotton wool balls, large polystyrene balls or toilet rolls and craft paper.