Bacteria in a Flask -- Spreadsheeting Population Density vs. Time part of Spreadsheets Across the Curriculum:General Collection:Examples
Over a period of 40 days following the injection of a bacterial inoculum into a sterile nutrient broth, the bacteria density in the culture increases from 40 cells/ML to 600 million cells/ML, and then declines to 1 cell/ML. The students tabulate and graph the data and identify the four stages: lag phase, exponential-growth phase, plateau phase, and death phase. They use both arithmetic and logarithmic ordinates to explore the rates of change in the various phases and see that each type of graph has its advantages and disadvantages. The module includes numerous prompts for students with little experience with Excel. The module can be used with a laboratory activity in which students gather their own microbiological data.
A Healthier You: Modeling a Healthier Weight from Dietary Improvement and Exercise part of Spreadsheets Across the Curriculum:General Collection:Examples
In this Spreadsheets Across the Curriculum module, students develop an Excel spreadsheet to calculate how many days it would take for an overweight person to come down to a healthy weight. The context is a community weight-loss program, and the presumption is that the student is designing a weight loss plan for the participants in the program. The weight-loss plan incorporates the effect of both dietary changes and increases in activity. The student's spreadsheet takes into account information relating to age, sex, height, weight, body mass index, resting energy expenditure, caloric content of food, and metabolic equivalents.