Science Fair Project Research Paper: An Apple a Day Keeps the Dr. Away, but What Keeps the Apple from Turning Brown?
An Apple a Day Keeps the Dr. Away, but What Keeps the Apple from Turning Brown?
What causes apples to turn brown? Apples turn brown when they are cut or bruised because their plant tissue becomes exposed to the air. When this happens an enzyme that is found in apple tissue, called polyphenol oxidase, reacts to the oxygen in the air and oxidizes the phenolic compounds to o-quinones. The o-quinones are what create the brown color by forming amino acids (McLandsborough, 2017).
The amount of polyphenol oxidase varies from fruit to fruit. The type of apple, as well as the maturity of the apple, make a difference in the amount of this enzyme the fruit has. Growing conditions can also affect the amount of this enzyme an apple contains. The lower the level of polyphenol oxidase, the less likely the apple is to brown after being cut. Similarly, potatoes contain an enzyme called catechol which reacts with the oxygen in the air to turn the flesh of the potato brown as well. With both apples and potatoes, the browning of the produces’ flesh is not desired, however, in some cases, the browning can be desired. Polyphenol oxidase is also what makes tea, coffee, and cocoa brown, which is, in fact, the desired color (McLandsborough, 2017).
How can this browning be prevented? There are a few ways to accomplish the prevention or the prolonging of the browning process. Firstly, this browning can be prevented by the addition of other substances. The use of sugar or syrup can slow the process of browning by limiting the amount of oxygen diffusion. Juice high in antioxidants, like lemon juice or pineapple juice, can also slow the process of browning. In addition, juices help slow the browning process because of their acidity. The additional acidity causes the apple to have a lower pH, thus causing the polyphenol oxidase to be less active (McLandsborough, 2017). Similarly, vinegar works in the same way because of its acidity. Another substance that can help prevent the browning of apples is ascorbic acid or vitamin C. The ascorbic acid is not only effective in preventing the apple from turning brown, it does so without changing the flavor of the apple (Harris, Yada, & Mitcham, 2007). The addition of milk helps prevent the browning of apples to a certain extent because is a milk is an acid. Enzymes work best around the pH of 4.5 to 8 (BBC, 2014). Milk is around a pH of 6.5, so because it is only slightly acidic, it prevents the browning process for a short time. It will not prevent the browning as long as lemon which has a pH of 2.
Aside from coating the apples with different substances, the freshness of apples can also be prolonged through different processes. When an apple is boiled, the enzyme polyphenol oxidase is almost completely deactivated. However, when the apple is boiled, the texture of the apple changes (McLandsborough, 2017).
In this experiment, the research was put to the test. The experiment was designed to test the ability of lemon juice, vinegar, olive oil, soda, and milk to prolong the viability of apple slices by preventing the browning of their flesh. Coming into the experiment, the hypothesis was “If an apple slice is coated in olive oil, then it will take longer to brown than an apple placed in any other substance because the properties of olive oil will prevent oxygen, which causes the reaction to turn the apple brown, from reaching the flesh of the apple.” To test this hypothesis, three golden delicious apples were cut into 18 equal slices and immediately placed into bowls containing two tablespoons of each substance. Three slices were placed in each bowl and they were flipped over until they were completely coated with the substance. The slices were then placed onto paper plates and left to dry in the air. Three slices were set aside on a paper plate as the control. As the apples were resting on the paper plates. They were periodically checked, observed, and pictures were taken. Notes were recorded on each slice on the color, rough percentage of brown, and texture when applicable. The observations were taken every one to three minutes for a total of 107 minutes. The process was a bit overwhelming to collect all of these details, but with the help of an assistant to help with the initial setup, it was manageable.
As a result, it was inferred that as a combination of the percentage of brown on the apple slices, the darkness of the brown, and the time that it took for the flesh of the apples to turn brown, the best substance to prevent brown on the apple slices was lemon juice. In a contrast to the initial hypothesis, olive oil was the worst substance in preventing the browning of the apple slices. Not only did the olive oil turn the apples a yellowish beige color, but it caused the apples to turn the most evenly dark brown color. It was hypothesized that olive oil would be the best substance because the research had said that syrup can prevent the browning of apples because of the restricted oxygen diffusion. Though olive oil is not as thick as syrup, it is a thick substance and it would be logical to think that a coating of olive oil would function in the same way. The lemon juice was supported by the research as well. It was successful because of both its vitamin C and its low pH that act as inhibitors, denaturing the enzymes in the apples.
The vinegar had an outcome that was relatively comparable to the lemon juice. Two of the three apple slices remained white for more than half of the observations. However, by the end of the observation, all three of the slices had at least started to brown. The soda was semi-successful as well because the sugar which the research also states is a way to prevent the oxygen diffusion. All of the samples did fall victim of outliers. Since the apples were all picked on the same day, from the same apple orchard, the variables were controlled as much as possible. However, as the research states, all apples vary in the amount of polyphenol oxidase.
This project and any other science fair project are very important for students to carry out. Science fair projects allow students to fully develop their knowledge of the scientific method and the skills of inquiry. Science fair projects can be very authentic ways of learning the scientific method if they are designed around a real-life question that can yield a useful answer. This experiment is one of the science fair projects that creates an authentic understanding of the scientific method because many parents and children run into the problem of browning apples when they wish to pack a healthy snack for lunch. The results of this experiment can help parents avoid this dilemma when packing snacks for their children without having to use prepackaged apples or a less healthy option. Also, this experiment helps the students develop their knowledge of science through the use of the CORE Model. This model has four parts Connect, Organize, Reflect, and Extend. The Connect phase requires the students to connect their knowledge by brainstorming, collaborating with others, and doing hand-on-science (Miller, & Calfee, 2004). Science fair projects fulfill these requirements, especially when they are allowed to work with a partner. Allowing the students to brainstorm with each other can help them fully develop their understanding of the scientific method because children learn more efficiently from their peers. The Organize phase requires the students to create a graphic organizer to help them organize the data they are collecting (Miller & Calfee, 2004). This is an important step in a science fair project because as any project goes along, there can be far too much data to sort through and understand. These graphic organizers work as the prewriting phase of the project (Miller & Calfee, 2004). The students can be better prepared to write about their results when they can see their data clearly laid out in front of them.
After the data is collected, the next phase is the Reflection phase. In this step, the students self-evaluate and reflect on their learning experience. The students discuss with each other during this stage to further deepen their knowledge and make final preparations for their writing assignment. The student then must put all of their knowledge together and complete a writing prompt that their teacher helps break down for them. It is important that the teacher gives the students a rubric to follow along with that breaks down the prompt so that their responses come back more developed and thought out (Miller & Calfee, 2004). The step of self-evaluation and reflection on the work the students have done is very important. The step is very similar to the discussion and analysis of the science fair project. In this step, the student can look back at what the did and assess how these steps brought them to their conclusion and how the results support or challenge their hypothesis. It also allows them to wrap up the scientific method and reflect on the steps that they took to get them to the end result. Finally, the students reach the Extend phase. In this phase, the students research further on their topic to expand their knowledge. The students then share their findings with their classmate (Miller & Calfee, 2004). This is similar to the science fair project as well. The student can all research topics that are interesting to them, carry out experiments and research on the topic, and then share their findings with their classmates. By sharing with their classmates, it expanded the whole classes knowledge on their topic and allows the students’ hard work to be celebrated.
Some of the Next Gen Science Standard that could be applied to this project are, 4-ESS2-1 (Make observations and/or measurements to produce data to serve as the basis for evidence for an explanation of a phenomenon), 4-ESS2-2. (Analyzing data in 3–5 builds on K–2 experiences and progresses to introducing quantitative approaches to collecting data and conducting multiple trials of qualitative observations. When possible and feasible, digital tools should be used), and 4-ESS1-1. (Identify the evidence that supports particular points in an explanation). These standards apply to the fourth-grade curriculum. Some of the Common Core writing standards that could be used are CCSS.Writing.Grade 4.1B (Provide reasons that are supported by facts and details), CCSS.Writing.Grade 4.4 (Produce clear and coherent writing in which the development and organization are appropriate to task, purpose, and audience), CCSS. ELA-Literacy.SL.4.1 (Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 4 topics and texts, building on others' ideas and expressing their own clearly), and CCSS.ELA-Literacy.SL.4.1.C (Pose and respond to specific questions to clarify or follow up on information, and make comments that contribute to the discussion and link to the remarks of others). All of these standards combine really define the process of inquiry. The student must ask the question, make observations, and use those observations to support a conclusion. It is amazing how well this type of project reflects the fourth-grade curriculum. To modify this project for younger and/or older grades, a teacher could easily change the standards to better suit her learners.
I thought the aspect of Voicethread was really interesting. I thought it was very easy to use and I really liked how all of our slideshows could come together in one place for everyone to comment on. I think that this would be a very useful tool in my future classroom. I would be able to do something similar to our science fair project to have students create a collaborative Voicethread. Voice thread would be a very fun way to have the students do a getting to know you activity by making video comments on theirs and others' slides. I thought that commenting questions and having our classmates respond on the Voicethread was very interesting. I felt like having the videos and voice recordings made the comments feel more personal. I am excited to get some questions on my project!
My group mates had some interesting science fair projects. Nessiah had created a project to filter water in the hopes of understanding what people who live without clean water have to go through in their everyday lives. I thought this was a very meaningful experiment that, if done on a larger scale, could impact people's lives. Allie created an experiment to find out if ocean water, salt water, could every freeze. This experiment was very interesting because I did not know if salt water could or not either. Her results were very fascinating, the salt water actually froze but it was cloudy and had a rough texture. I wonder if there is a way to get salt water to freeze clear? Alisha's experiment was on the effect of sugary and acidic drinks on teeth using eggs. I thought it was really cool that eggs were so similar to teeth enamel. I thought her experiment was very informative and provided great insight into the damaging effects of drinks like soda, Gatorade, and orange juice on teeth. I was very surprised at how much the orange juice affected the eggshell. When I think of orange juice, I think of a healthy drink. Now after seeing what it did to the eggshell, I am a bit more wary of drinking it and if I do, I'll surely brush my teeth right after!
Some of the Next Gen Science Standard that could be applied to this project are, 4-ESS2-1 (Make observations and/or measurements to produce data to serve as the basis for evidence for an explanation of a phenomenon), 4-ESS2-2. (Analyzing data in 3–5 builds on K–2 experiences and progresses to introducing quantitative approaches to collecting data and conducting multiple trials of qualitative observations. When possible and feasible, digital tools should be used), and 4-ESS1-1. (Identify the evidence that supports particular points in an explanation). These standards apply to the fourth-grade curriculum. Some of the Common Core writing standards that could be used are CCSS.Writing.Grade 4.1B (Provide reasons that are supported by facts and details), CCSS.Writing.Grade 4.4 (Produce clear and coherent writing in which the development and organization are appropriate to task, purpose, and audience), CCSS. ELA-Literacy.SL.4.1 (Engage effectively in a range of collaborative discussions (one-on-one, in groups, and teacher-led) with diverse partners on grade 4 topics and texts, building on others' ideas and expressing their own clearly), and CCSS.ELA-Literacy.SL.4.1.C (Pose and respond to specific questions to clarify or follow up on information, and make comments that contribute to the discussion and link to the remarks of others). All of these standards combine really define the process of inquiry. The student must ask the question, make observations, and use those observations to support a conclusion. It is amazing how well this type of project reflects the fourth-grade curriculum. To modify this project for younger and/or older grades, a teacher could easily change the standards to better suit her learners.
I thought the aspect of Voicethread was really interesting. I thought it was very easy to use and I really liked how all of our slideshows could come together in one place for everyone to comment on. I think that this would be a very useful tool in my future classroom. I would be able to do something similar to our science fair project to have students create a collaborative Voicethread. Voice thread would be a very fun way to have the students do a getting to know you activity by making video comments on theirs and others' slides. I thought that commenting questions and having our classmates respond on the Voicethread was very interesting. I felt like having the videos and voice recordings made the comments feel more personal. I am excited to get some questions on my project!
My group mates had some interesting science fair projects. Nessiah had created a project to filter water in the hopes of understanding what people who live without clean water have to go through in their everyday lives. I thought this was a very meaningful experiment that, if done on a larger scale, could impact people's lives. Allie created an experiment to find out if ocean water, salt water, could every freeze. This experiment was very interesting because I did not know if salt water could or not either. Her results were very fascinating, the salt water actually froze but it was cloudy and had a rough texture. I wonder if there is a way to get salt water to freeze clear? Alisha's experiment was on the effect of sugary and acidic drinks on teeth using eggs. I thought it was really cool that eggs were so similar to teeth enamel. I thought her experiment was very informative and provided great insight into the damaging effects of drinks like soda, Gatorade, and orange juice on teeth. I was very surprised at how much the orange juice affected the eggshell. When I think of orange juice, I think of a healthy drink. Now after seeing what it did to the eggshell, I am a bit more wary of drinking it and if I do, I'll surely brush my teeth right after!
References
BBC. (2014). GCSE Bitesize: Enzymes. Retrieved November 23, 2017, from
http://www.bbc.co.uk/schools/gcsebitesize/science/add_ocr_gateway/living_growing/proteinsrev2.shtml
Harris, L. J., Yada, S., & Mitcham, E. (2007). Apples: Safe Methods to Store, Preserve,
McLandsborough, L. (2017). Why do apple slices turn brown after being cut? Retrieved October
Miller, & Calfee. (2004). Making Thinking Visible. Retrieved November 26, 2017, from
http://www.nsta.org/publications/news/story.aspx?id=49933
Hey Rebecca! Great blog post ! I really learned a lot about your experiment and I would love to conduct the same one in my future classroom!! have a good day:)
ReplyDelete