Scientific basis for the project

This activity uses the “yeast race” method. Flour, sugar, water and yeast are mixed in a Falcon tube. Respiration causes CO₂ gas to be generated, which creates bubbles that rise up the tube, creating foam that is proportional to the amount of fermentation. The quantity and type of sugar can be varied depending on the hypothesis chosen by each group.

Brief summary of each session

1. An introduction to the scientific method, controls, and the fair test; followed by a short presentation on the theoretical basis for the project, then time for groups to plan their work (could be in or out of the lab). 60-90 min.
2. Lab session: work in groups to perform the experiments after the briefest of introductions (a general lab induction has already been given). We normally ensure that groups sit together with some sort of labels on the benches as they enter the lab. 3 hours.
3. Data analysis (need at least one computer per group). We do this in the lab and students have the opportunity to repeat experiments if necessary (this is rare though). We expect a computer-generated graph for each group, which some find quite challenging. We’ve found that the best is not to give too many prescriptive instructions, but instead to let students make a start on their own and then help when they get stuck. 2 hours.
4. Tutorial: time is given in the next tutorial to discuss the experiment and the results. The idea is to get students comfortable discussing science with their peers and their tutor as soon as possible; this is not formally assessed. 15 minutes.

We run these on separate days but it would also work well as a full day activity.

Learning objectives

• Get to know the teaching staff and other students, and get used to working in the lab
• Discover concepts around the scientific method and experimental design
• Learn about note keeping and practise writing a lab book
• Write a basic report

If you decide to use this practical, please let us know about it by filling in this short form – it’s not a requirement but we’d love to hear how our ideas are being used!