Since cheese appears to go bad when left in the refrigerator for too long, it would be helpful to know if there are any cheeses that can endure longer without manifesting mold growth on their surface. The three cheeses used in this experiment (American, Swiss and Cheddar) are common but distinct. Differences in mold growth over time should be easy to observe.
Every experiment begins with a hypothesis. This is a conjecture or statement that the experimenter must prove true or false. In this case, the experimenter should have some assumption about which cheese will grow mold faster than the others. Since softness is a sign of moisture in cheese, and moisture encourages mold growth, the hypothesis should state that the softest cheese will display more mold after a given period of time passes.
Most elements and materials in an experiment should stay the same. These are known as constants. In this experiment, these constants would be the location of the cheese, the time period endured in storage, the temperature and humidity of the location and the amount of each type of cheese. In a fair experiment, the scientist has one independent variable that she controls. The types of cheeses are the independent variables in this case. The dependent variable is what the scientist observes and uses as the basis for evaluating the results. Mold is the dependent variable in this cheese experiment.
You will need exactly equal amounts of each type of cheese. In addition, you will need plastic bags to contain the cheese, rubber gloves to touch it and pen and paper to record your observations. To refrain from adding more variables to this experiment, these materials must be equal and used with all three cheeses in a similar fashion. You will also need some method for measuring the mold. You can use a transparent grid sheet to count the squares the mold covers to characterize each cheese's mold growth.
The procedure should be the same for each piece of cheese. As the experimenter, you should handle each piece of cheese in exactly the same way. Keeping good records and checking for mold growth regularly should also be integral parts of the experiment's procedures.
When the allotted time period is up, calculate how much mold growth has occurred on each piece of cheese. Write down an answer to your original hypothesis about which cheese would show more mold growth. Include information about how much mold each cheese had.