## Engaging with Hands-On Exponential Decay

8.6_cutting_yarn_activity.docx | |

File Size: | 14 kb |

File Type: | docx |

cs3_8.6_student_work.pdf | |

File Size: | 1100 kb |

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## Reflection

Again, the students continued to impress me with the number of assignments turned in with this assignment. During the lesson, students exclaimed that they thought the lesson was too easy, and that they knew that the more they cut the yarn, the smaller it would get. However, as I saw from their responses, some student still did not understand that the rate the yarn decreased in size could be modeled by exponential decay. Because the students had just worked with exponential growth, many of them tried to fit this situation into the growth model, instead of writing one for decay. Since we were still working on decay for another day, we had time to address any misconceptions brought up during the lesson.

The responses from this assignment could be categorized into two different sections: those who believed it wasn't an example of an exponential function, and those who did think it was an exponential function. The student work below shows examples of these two responses.

The responses from this assignment could be categorized into two different sections: those who believed it wasn't an example of an exponential function, and those who did think it was an exponential function. The student work below shows examples of these two responses.

In the above student work, the student did the correct work. #1 was an example of exponential growth, while #2 was an example of exponential decay. This student, like many of the other students, believed that an exponential function had to be growth. This misconception was addressed in the next lesson, and did not seem to produce any confusion after this.

The work below shows a student who understood that an exponential function could be an example of decay as well, producing the correct decay rate, using the exponent as the variable. Something I noticed in both sets of student work, as well as in other students' work, was that for 2c, they wrote that the length after the 10th cut was 9.76. After investigating, I realized that students weren't translating the scientific notation from their calculators, which gave me a great opportunity to bring this up 3 lessons later when we learned about scientific notation.

The work below shows a student who understood that an exponential function could be an example of decay as well, producing the correct decay rate, using the exponent as the variable. Something I noticed in both sets of student work, as well as in other students' work, was that for 2c, they wrote that the length after the 10th cut was 9.76. After investigating, I realized that students weren't translating the scientific notation from their calculators, which gave me a great opportunity to bring this up 3 lessons later when we learned about scientific notation.

Since this was the last assignment of this unit, I was increasingly interested to see how many students turned in their homework for this assignment. For the first time this year, every single student turned in something for this assignment! Being that my main focus this semester has been increasing student motivation in turning in homework, and showing that they cared about their homework grade, I was very pleased to see this result.