

![]() | Project title | A comparison on the contamination of wet and dry food![]() ![]() |
| Difficulty Level | Middle school | |
| Project page |  Click here to view this science project | |
Description | ||
| The objective of this science fair project is to determine the type of food – wet or dry food – that is most prone to germ contamination. The experiment will be carried out by dropping a slice of cucumber (wet food) and a piece of cheese cracker (dry food) for 20 seconds at various locations. | ||
Instructions preview | ||
| 1. The independent variable in this science fair project are the locations where the cheese cracker and cucumber slice were placed – kitchen sink, toilet floor, car porch or garden grass. The dependent variable is the amount of bacterial growth in the Petri dishes, which is determined by counting the number of bacteria colonies. The constants (control variables) are the temperature of the room, the amount of sunlight, and the ingredients used to make the agar in the Petri. 2. Store the eight Petri dishes in a refrigerator. Before the start of the experiment, take the Petri dishes out ..... | ||