| Explore | Plants have chlorophyll, a green pigment necessary for photosynthesis. Their cell walls are made by a structural material called cellulose, they are fixed in one place, and we know that plants harness the sun’s energy to photosynthesize. We are also well-aware that plants also use water and carbon dioxide to make energy. Plant cells have structural polysaccharide called the cell wall. Some questions we have include: What four things do all plants need? What are the parts of the plant? What are their functions? What is the first stage in the growth of many plants? Regarding potatoes, we found out that soft rot of potatoes has been caused by a range of bacteria around the world such as Pectobacterium carotovorum subspecies carotovorum, Pectobacterium atrosepticum, and Dickeya species. Soft rot is defined by the softening of the infected tissue, which is often accompanied by discoloration and an overpowering odor (which we have sadly experienced). Most importantly, in order for a disease to impact a crop, three factors must be present at the same time: (1) a susceptible host, (2) a virulent pathogen, and (3) a conducive environment. |
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| Research Question | We are interested in testing whether the average temperature of the potato affects bacterial growth, and if so in what way. From listening to our peers' potato rot experiments we noticed that some left theirs in the sun, which resulted in increased odor from the potato. We know that in order for a disease to impact a crop, three factors must be present at the same time: (1) a susceptible host, (2) a virulent pathogen, and (3) a conducive environment; this question relates to the environmental aspect. |
| Predictions | We infer that the warmth will stimulate bacterial growth within the potato and the potato will be more affected. Conversely, the potato's symptoms and characteristics would be altered by a smaller factor when left in the cold (cooler) environment. Thinking back on past experiences with streak-plating bacterial cultures, the dishes were always places within an incubator to stimulate growth. Another experience taken into consideration was the refrigeration of food; a fridge alters the conditions of the surrounding environment so that the food will remain cold. As a result, bacteria doesn't grow; thus, we can assume that bacteria grows less in cold environments. |
| Experimental Design | Our plan is to repeat the original experiment with three different potatoes in three different environments. The first environment will be at room temperature, the second will be in a warm/hot environment (microwaved) and the third will be in a cold environment (refrigerator). The independent variable of this experiment is the temperature, while the dependent variable is the effect on bacterial growth. We will measure the average temperature of the potato; when the experiment has concluded, we will observe which potato supplied the most bacterial growth throughout the span of 5 days. |
| Investigation Theme | PGST |
| Grade Level | High School Students (Grades 9,10,11,12) |
| School Name | California Academy of Mathematics and Science |
| Session | Fall 2020 |