Description: Simple cultures and models illustrate how cells and bacteria multiply and why growth can be exponential.
Objective
Show exponential growth with safe classroom models and visualize basic cell structures.
Materials
- Dry yeast, sugar, warm water (closed containers)
- Agar substitute or gelatin plates (non-pathogenic, demo only)
- Measuring cup, timer, graph paper
- Printed diagrams of cell types
Procedure
1. Mix yeast, sugar, and warm water in identical containers.
2. Record gas production or volume change at fixed intervals.
3. Plot time vs. observed change to reveal growth curve.
4. Compare prokaryotic vs. eukaryotic cell diagrams.
Discussion
- Why early growth appears slow, then speeds up.
- Limits: nutrients, space, temperature.
Safety
Closed containers only. No unknown environmental samples.
Conclusion
Repeated doubling explains rapid increases in populations under favorable conditions.
