| Explore | What is the definition of disease? Negative effects caused by nonphysical trauma. What is the definition of a pathogen? Virus/bacteria that causes deadly diseases. What are the three variables that must exist for disease to occur? External agent, a host, and an environment that brings the two together. What is the difference between infection and colonization? Infection is the process of being contaminated and colonization is the action by a plant/animal establishing itself somewhere. What are some threats to our food supply? Insufficient population, greed, and other animals. What can growers do to overcome challenges in getting food to the table? Advertise whatever they are growing. Outside School Knowledge: - Plants do photosynthesis -Animals > Plants -Plants use roots to get nutrients from ground -Plants have different diets -Plants are usually healthy to eat unless otherwise -Plants sometimes use animals for protection and spreading seeds Questions about how plants because they're weird: -Did Plants back then need other partner plants to sexually reproduce? -Did Plant Cells evolve over time due to the meteor 65 millions years ago? -Did Plants develop a Stronger structure to defend themselves from the herbivore dinosaurs? Background Research: -Rotten Potatoes emit toxic gas :( -Soft Rot: -Caused by bacteria(Enterobacteriaceae) in soil or transmitted via insects. There is very little odor and this kind of rot can only happen if there is an opening to the tuber (Storage for nutrients) Temperature wise. Soft rot can occur 16 Celsius to above 35 Celsius. -Leak/Shell rot: Leak or Shell Rot. Several species of the fungi Pythium cause this rancid internal decay of potato tubers. ... Like soft rot, the fungi cause disease only if they enter the tuber through a cut, abrasion, or swollen lenticel -Pink Rot: appears as a decay of tubers that usually begins at or near the stem end of potatoes in the field or through eyes of potatoes in storage. Infected tissue becomes somewhat rubbery but not discolored. -Blackleg: A bacterial disease in potatoes, which causes black rotting at the stem base. They are stunted and have an erect growth habit. Primarily the stem decays, but other parts of the potato wilt as well. -Brown rot: Also known as bacterial wilt is one of the most destructive diseases of potato. Symptoms may include discoloration of the potato and a milky white ooze which indicates the presence of bacteria cells inside the potato. Inoculation Procedure: 1. Get a new potato, no slicing, rinse it with H2O. 2. Deposit the potato in 10% bleach solution for 30 minutes and let it dry on a cloth for at least 30 minutes. 4.Take a toothpick and transfer some of the inoculum then pierce it onto four different sides of the potato's surface. 5. Dispose the toothpick and wrap the potato in a wet cloth. Close the container of the inoculum and deposit the potato in a new clean container with a label. Experimental Research: We are trying to observe the mass, length, color, texture, temperature, smell, and density of the potato that have been inoculated and deposited in a new bag for at least a week. We record the data at 2:30 p.m. daily starting from the day of the inoculation. This is for the sake of microbiological research and forming our own questions. Results:(This data might be confounded because the potato might of absorbed too much bleach and killed any bacteria injected into it.) Day 0: Time: 5:00pm Color: Mostly Yellow Smell: Mostly potato smell and some bleach smell Texture: Somewhat sandpaper like Mass: 144.2g Temperature: 24 C Dimensions: 65mm*80mm*60mm Density: Solid Day 1: Time 8:25 AM Color Mostly yellow, but some brown Smell: Smells the same as yesterday Texture: Still feels like sandpaper Mass: 143.9g Temperature: 23.3 C Dimensions: 65mm*80mm*59mm Density: Solid Day 2: Time: 8:23 AM Color: Same as yesterday Smell: The bleach smell is gone Texture: A little bit smoother Mass: 142.8g Temperature: 24 C Dimensions: 60mm*80mm*59mm Density: Solid Day 3: Time: 12:30 PM Color: A little more brown Smell: Same as yesterday Texture: Same as yesterday Mass: 145g Temperature: 24 C Dimensions: 57mm*79mm*59mm Density: Solid Day 4: Time: 10:00 AM Color: Maybe a little bit of black but definitely more brown. Also a white spot is on the potato. Smell: The same as yesterday Texture: It feels rough in some areas and smooth in others. Mass: 144.5g Temperature: 23.5 C Dimensions: 57mm*79mm*55mm Density: Solid Day 5: Time: 8:20 AM Color: More brown and multiple white spots Smell: Smells a little bit like rotten potato Texture: Same as yesterday but more extreme Mass: 144.6g Temperature: 23.4 C Dimensions 57mm*75mm*55mm Density: Solid Day 6: Time: 8:20 AM Color: White spots have grown and noticeable black spots (Not at injection site) Smell: It has a potent potato smell Texture: A little sticky Mass: 144.8g Temperature: 24 C Dimensions: 57mm*75mm*50mm Density: Solid Day 7: Time: 8:24 AM Color: White spots are covering a lot of the potato Smell: Smells like a potato rotting and not rotting at the same time Texture: Smooth on one side (Not at a injection site) Mass: 144.7g Temperature: 24 C Dimensions: N/A Density: Somewhat mushy Rotten potatoes: Smell, Poison, Health risks and More. (n.d.). Retrieved October 05, 2020, from https://www.tracewellness.com/2019/08/rotten-potatoes.html Soft rot diseases of potatoes. (n.d.). Retrieved October 05, 2020, from https://www.agric.wa.gov.au/potatoes/soft-rot-diseases-potatoes Pavlista, A. D. (2013). Wet Rots in of Potato in Storage. Retrieved October 05, 2020, from https://extensionpublications.unl.edu/assets/pdf/g2203.pdf Hirsch, R., Miller, S., & Halterman, D. (2018, October 01). An Inquiry-Based Investigation of Bacterial Soft Rot of Potato. Retrieved October 05, 2020, from https://online.ucpress.edu/abt/article/80/8/594/19103/An-Inquiry-Based-Investigation-of-Bacterial-Soft Bacterial Soft Rot and Blackleg. (n.d.). Retrieved October 05, 2020, from https://www2.ipm.ucanr.edu/agriculture/potato/Bacterial-Soft-Rot-and-Blackleg/ |
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| Research Question | Actual Research Questions How does a concentration of bleach affect the growth of bacteria injected into the potato? What do we want to test or study? We could have a control group potato where we don’t put it into a bleach solution (maybe just a water solution) and have experimental groups where we add different concentrations of bleach (10%, 5%, 2%, 0%) so that we can see if there was an effect the bleach had on the potato rot of each potato. We would take the same data, (maybe add the different concentration of bleach and amount of water too in mL) over a 7 day period. After that 7 day period, we would record the differences, if there are any, of the different potatoes. We could cut the potatoes in half to see the inside effects of the potato rot as well. How did we come up with the question(s). How does the question fit what we know about the topic? We came up with this idea because we had the suspicion that because our potato was smaller than other groups, our concentration of bleach might have been too high for the size of the potato to handle, because our potato seemed less rotten than other groups. We’re wondering if we had added a lower concentration of bleach or maybe no bleach at all, if that would have made the potato become more rotten over the 7 day period. |
| Predictions | Predictions What are the possible outcomes of our study given the variables we are working with? As the bleach concentration is lowered, the effects that the bacteria has on the potato will be stronger. In other words, the potato will exhibit more negative symptoms like discoloration, pujdant smells, and potential changes in weight as less bleach is introduced. What is our explanation for why and how we think this will happen? This will most likely happen because with less bleach, the bacteria inside the potato will not die and have a chance to replicate. The bleach might not penetrate as far into the potato and therefore, not kill as many bacteria. |
| Experimental Design | Purpose: To observe four potatoes and compare the effects of differing concentrations of bleach solution on the development of potato rot. Hypothesis: Bleach is known for its disinfecting properties, so it's safe to predict that if a potato is soaked in a higher concentration of bleach solution, it would inhibit the development of potato rot more than a lower concentration of bleach solution would. Materials: 4 Potatoes, 4 Containers, Ziplock bags, Bleach (Clorox), Thermometer, Balance Scale, Water (Tap water), Toothpick, Disposable gloves, Brush, Paper towels, Potato inoculum. Procedure: Constant variables: Amount of time of cleaning potatoes, Time of day to observe each potato, Amount of time agitating the potatoes, Way the potato data is recorded, Air pressure, Amount of solvent that the potatoes are soaked in, The temperature that the potatoes are exposed to, Amount of light the potatoes are exposed to. Step 1: Prepare 3 containers with differing bleach solutions (2%, 5%, and 10%) in 200mL of water. The fourth container has only 200mL of water. Label 4 ziplock bags with ‘no bleach’, ‘2% bleach’, ‘5% bleach’, and ‘10% bleach’. Calculations ; 2% Bleach Solution: 200mL Water * 2mL Bleach/100mL Water = 4mL Bleach 5% Bleach Solution: 200mL Water * 5mL Bleach/100mL Water = 10mL Bleach 10% Bleach Solution: 200mL Water *10mL Bleach/100mL Water = 20mL Bleach. Step 2: Gather four potatoes of about the same size/mass and wash them with water using a brush. Clean them for about 5 minutes. Step 3: Put each potato into a container by itself because each potato will take a different solution of bleach. For the next 30 minutes, agitate the containers holding the potatoes. After the 30 minutes, leave the potatoes to dry on paper towels for about another 30 minutes. Step 4: While the potatoes are drying, clean the containers that are used for the solutions with soap and a new sponge for lab purposes to avoid contamination of the normal kitchen sponge used normally. Let them air dry when done cleaning. Step 5: Once the potatoes have dried, use a toothpick and dip it into potato inoculum. Inoculate each potato - penetrating the potato, implanting bacteria into it - and put each potato into the corresponding ziplock bag surrounded by damp paper towels. If the containers are all cleaned up, put the ziplock bags into the containers. Step 6: Every day, over a 7 day period, at the same time of day, record the temperature with a thermometer (celsius), mass (grams) with a balance scale, feel, smell, color, and texture of each potato. Step 7: On the last day, cut each potato in half to record what the insides look like. Step 8: Once finished taking data, clean containers with soap and dispose of rotting potatoes, plastic bags, paper towels, and old sponge that was used to clean the containers into the garbage. Data: *data will be recorded on a spreadsheet and will be transferred here once the data-taking process is finished* |
| Conclusion | Claim: The result of the experiment indicates that the amount of bleach a potato is disinfected in does not affect the inoculation process or bacteria growth. The initial hypothesis that bleach would be effective to stop bacteria growth in higher concentrations was inconclusive, because there’s no clear evidence that the amount of bleach was successful or not in inhibiting the development of bacteria. Evidence: On day 12 for the first trial, the no bleach potato had formed a big white mass, but the 10% bleach potato had multiple black masses on its surface. Yet, 2% and 5% bleach potatoes only show signs of discoloration and slight greenish colors. The results follow the same pattern in the second trial, where on day 14, the appearance of 0%, 5%, and 10% bleach potatoes showed little bacteria growth on the inside, but the inside of the 2% potato was almost completely engulfed by bacteria inside. Again similar results in trial 3, the 5% potato on the last day, when cut and compared to the other potatoes, there was more bacterial growth inside, than all three combined. Reasoning: If the bleach was effective in the first trial, the 10% bleach potato would have looked similar to the 2% and 5% bleach potatoes. But if the bleach was ineffective, the 2% and 5% bleach potatoes would have more bacterial growth like the 10% bleach potato. Likewise, if the bleach was effective in the second trial, the 2% bleach potato would have appeared and smelled similar to the other potatoes in the trial. But if the bleach was ineffective, the 0%, 5%, and 10% bleach potatoes would have been as bad as the 2% bleach potato. Or in the third trial, where the 5% potato had more bacteria than the no bleach, 2%, and 10% potatoes. The bleach was effective in the 2% and 10% potatoes, but ineffective in the 5% potato. Even though bleach is known as a disinfectant/sterilizer that kills bacteria, it’s somewhat a paradox in regard to the final data. Restating the results, it’s inconclusive that bleach is a reliable substance that’s able to stop the growth of potato rot. |
| Investigation Theme | PGST |
| Grade Level | High School Students (Grades 9,10,11,12) |
| School Name | California Academy of Mathematics and Science |
| Session | Fall 2020 |