We made it! It's hard to believe that it is already the end of the semester but good too know that we have leaned so much. I just wanted to let you all know that I have enjoyed working with you guys and reading your blogs over the past few months. I wish you luck in the coming semesters and in your future teachings!!
Circumference and Diameter-Annenberg Video
- Describe Ms. Scrivner's techniques for letting students explore the relationship between circumference and diameter. What other techniques could you use?
I think Ms. Scrivner did a great job of helping her students gain understanding of the concepts of circumference and diameter. After reviewing the terms, she introduced them to the hands on activity they later completed. I like how she let the students sort of help her explain the directions by showing them the charts each group would be using. She focused on helping them understand that each column indicated a different measurement--the circumference and diameter. The way these columns were laid out later helped them see a relationship between the two. The act of measuring and recording data for different items also helped students see connections between the numbers for the different columns. They saw that the numbers for diameter were smaller than that of the numbers for each item's circumference. When sharing these findings with the class, it was great that an item from each group's list was shared on he overhead. While focusing on the measurements of the cork with a circumference of 6 cm and a diameter of 2 cm that one group found, Ms. Scrivner prompted students to discuss a possible connection between the numbers. The class found that multiplying the diameter by 3, you would reach the measurement of the circumference (which implies that dividing the by 3 would result in the circumference). I like how the students were able to come to this conclusion on their own, without being directly told by the teacher. By completing this activity, they were able to gain practice with the idea of division. Moreover I could see how this lesson could be the precursor to a lesson about finding Pi (π) (3.141592...) which is actually the ratio of the circumference to the diameter. Even though the students did not have decimals in their measurements, you must remember that they rounded their numbers to the nearest centimeter. Just a thought.
Another technique that can be used to help students in this area is by measuring other circular objects with different colored pieces of string or yarn. Each group would cut the string at the length of what they measure. For example, a green string could represent the circumference of the object while a red string represents the diameter. Students can compare the lengths of the string by placing them side by side and observing the difference. Some children might see that it takes a little over three diameter string lengths to match the length of the circumference. I think this would be a good thing to use before introducing students to working with numerical measurements.
- In essence, students in this lesson were learning about the ratio of the circumference to the diameter. Compare how students in this class are learning with how you learned when you were in school.
I can't say that I remember learning too much about these concepts in school but I do recall much of the instruction in my middle school and even high school years. The students learned about the circumference and diameter using hands-on activities and group interaction. This is much different from how I learned these concepts because my teachers had us memorize formulas and definitions. As a young student, I would have been able to tell you how to find the radius and measure circumference and diameter but I wouldn't have been able to explain why certain formulas are used and why they work. I think that if my former classmates and I were engaged in inquiry investigation like Ms. Scrivner's students, we would have had a better grasp on the meanings behind the concepts. - How did Ms. Scrivner have students develop ownership in the mathematical task in this lesson?
As mentioned earlier, I really like how Ms. Scrivner allowed students to essentially guide the lesson. She asked individual students to look at the measuring data chart and share their thoughts on what they were going to do. I think this really helped them understand the objectives and remember directions. The activity itself gave students the freedom of choosing what they wanted to measure. They were responsible for working with their group members to take their own measurements and then filling out the data chart. I like how the video showed some students even taking ownership of their mistakes. For example, one group was seem measuring the height of the trash can for the diameter while another group decided to measure one classmate's head--which is actually an oval and not a circle. I like how Ms. Scrivner allowed students to work through these issues and make the necessary adjustments.
The whole-group review time/closing also served as an opportunity for children to take ownership of the lesson because the teacher instructed students to share their findings with the class. In order to determine the relationship between circumference and diameter, the students worked together to share thoughts and ideas. I like how the teacher kept notes on the overhead to guide student thinking rather than just "feeding" them the answers. Essentially, this is how students developed ownership--through guidance and prompting. - How can student's understanding be assessed with this task?
I think students can be assessed with this specific task by observation and checking the data charts children fill out. The teacher is able to see which students understand the difference between circumference and diameter by watching what the are measuring. Similarly, it would be easy to spot discrepancies in student work when looking at the measurements on the paper. If their numbers indicate a longer length for the diameter, then this could indicate that they either put the numbers in the wrong box, measured incorrectly, or measured an incorrect part of the item. They could also be assessed on completing the division portion where they use calculators to divide the diameter by the circumference (C/D). If they provide the wrong answer or list an strange number, this could mean they require more time and practice with the activity or concept.
Circles and Pi-Annenberg Module
I'm not going to lie. This was a really tough module! It's been a while since I worked with these concepts so I was easily stumped. Nevertheless, I did the best I could as I worked through each section.
Part AProblem A1: Use the designs to fill in the table below. For the circle, use string to approximate the circumference.
I don't know about you, but I didn't like this question/activity because it was really hard for me to measure the shapes accurately with the string. I couldn't hold it in place when measuring their circumferences...so I just looked at the solution. I was able to reach the correct answers for the diameter, but that was about it.
Problem A2: Look closely at the three designs. What patterns do you see in their measurements?
I thought this was a bit of a confusing question but just by looking at the 3 shapes, it is clear that the diameter increases by 2 as the shapes get bigger. The sides of the hexagon increase by one. The solution shares more information but these are what stood out the most for me.
Problem A3:
a. For each design, how does the diameter of the circle
compare to the perimeters of the square and the hexagon?
In order to answer this question, it helped to write out the numbers and find the pattern. It is clear to see that for each design, the perimeter of the square is 3 times the diameter and the perimeter of the hexagon is 4 times the diameter.
b. For each design, how does the approximate circumference
compare to the perimeters of the square and the hexagon?
This one was a lot harder to solve. I tried to work it out on paper but I easily became confused so I had to look at the solution. After reading it, I did see that the approximate circumference of the circle lies between the perimeter of the square and the perimeter of the hexagon.
This one was a lot harder to solve. I tried to work it out on paper but I easily became confused so I had to look at the solution. After reading it, I did see that the approximate circumference of the circle lies between the perimeter of the square and the perimeter of the hexagon.
As you can see, I was able to determine that the circumference of these circles is about 3.15 or 3.2 cm more than their diameters. Knowing this, I took 3.2 and multiplied it by 7cm to make my prediction. I was correct to say that a circle with a 7cm diameter would have an approximate circumference of 22cm.
Problem A4:
a. For each object, estimate the circumference. Then measure the circumference and the diameter in centimeters to the nearest tenth (e.g., millimeters). Use string or a tape measure. Record your data in the table.
a. For each object, estimate the circumference. Then measure the circumference and the diameter in centimeters to the nearest tenth (e.g., millimeters). Use string or a tape measure. Record your data in the table.
b. Examine the table. What do you notice about the ratio of
C to d? Based on these data, what is the relationship between the diameter and
circumference of a circle?
As seen throughout this module, dividing the circumference by the diameter produces the same, or similar values. In this case, all of my values are 3 or very close to 3.
As seen throughout this module, dividing the circumference by the diameter produces the same, or similar values. In this case, all of my values are 3 or very close to 3.
Problem A5:
a. Enter the values from the table for diameter and circumference into a graphing program in your computer or into a table in your graphing calculator to make a scatter plot. Use the horizontal axis (x) for diameter and the vertical axis (y) for circumference. Graph the points. What patterns do you see in the graphical data?
a. Enter the values from the table for diameter and circumference into a graphing program in your computer or into a table in your graphing calculator to make a scatter plot. Use the horizontal axis (x) for diameter and the vertical axis (y) for circumference. Graph the points. What patterns do you see in the graphical data?
b. What information does a graph of these data provide?
Even though I have a graphing calculator, I will say that I completely forgot to use this particular feature so I skipped it this problem.
Even though I have a graphing calculator, I will say that I completely forgot to use this particular feature so I skipped it this problem.
Problem A6: Find the mean of the data in the C/d column. Why find the
mean? Does the mean approximate ?

I wasn't so sure why it was necessary to find the mean but I did learn that it is to ensure that no errors were made in previous problems. By finding the mean, I was able to reach a value that was close to Pi.
Problem A7: The symbol r represents the radius of a circle. Explain why C =
• 2r is a valid formula for the circumference of a circle.
Now that I know the reasoning behind Pi, it makes sense why this is an accurate formula to find circumference. We know that we have to multiply Pi by the diameter to find the circumference. 2r is another way to represent diameter so essentially, this would read C=Pi times d. I hope this makes sense.
Now that I know the reasoning behind Pi, it makes sense why this is an accurate formula to find circumference. We know that we have to multiply Pi by the diameter to find the circumference. 2r is another way to represent diameter so essentially, this would read C=Pi times d. I hope this makes sense.
Problem A8: An irrational number cannot be written as a quotient of any two whole numbers. Yet we sometimes see
This question was a little confusing but peeking at the answer helped me a little. It does makes sense that we use these two things in various situations. There are times when you are unable to measure real items using π.
This question was tough, too. I learned that both of these items cannot be irrational at the same time. It can only be one or the other. The circumference can be irrational which would make the diameter rational. Vice versa, the circumference can be rational while the diameter is irrational.
Problem A10: When mathematicians are asked to determine the circumference
of a circle, say with a diameter of 4 cm, they often write the following:
C = π • d = π • 4
In other words, the circumference of the circle is 4 cm. Why
do you think they record the answer in this manner? Why not use the π key on the
calculator to find a numerical value for the circumference?
I would say that just typing these items into the calculator would not yield accurate answers. Mathematicians often look for precise numbers, not approximate numbers
I would say that just typing these items into the calculator would not yield accurate answers. Mathematicians often look for precise numbers, not approximate numbers
Part B
Problem B1: How does the area of the figure compare with the area of the circle?
The area is still the same. The only difference is the appearance because the circle has been cut up and arrange in a different way.
The area is still the same. The only difference is the appearance because the circle has been cut up and arrange in a different way.
Problem B2: The scalloped base of the figure is formed by arcs of the circle. Write an expression relating the length of the base b to the circumference C of the circle.
I was super confused by this question. I had no idea how to form this as an expression but the solution helped to some degree. I take it that the expression would be C/2 because the top and bottom scallops make up half of the circumference. (??)
Problem B3: Write an expression for the length of the base b in terms of the radius r of the circle.I was super confused by this question. I had no idea how to form this as an expression but the solution helped to some degree. I take it that the expression would be C/2 because the top and bottom scallops make up half of the circumference. (??)
Again, I had to look at the answer for this question. It made a little sense that since the new figure is 1/2 the circumference, then you would take 1/2 of the radius. So instead of it being 2πr^2, the new formula would be πr.
Problem B4: If you increase the number of wedges, the figure you create
becomes an increasingly improved approximation of a parallelogram with base b
and height r. Write an expression for the area of the rectangle in terms of r.
Think about how the activity involving wedges helps explain
the area formula of a circle, A = π • r2.
This question lost me! From reading the solution, I can see why the more number of wedges makes a much straighter line--simply because there are not as many scallops in the top and bottoms. I am just a little confused as to why, that if this is different, πr is still being used. Nevertheless the correct formula for this problem would be π X r X r.
This question lost me! From reading the solution, I can see why the more number of wedges makes a much straighter line--simply because there are not as many scallops in the top and bottoms. I am just a little confused as to why, that if this is different, πr is still being used. Nevertheless the correct formula for this problem would be π X r X r.
Problem B 5: Use the circles (PDF document) to work on this problem. For each circle, cut out several copies of the radius square from a separate sheet of centimeter grid paper. Determine the number of radius squares it takes to cover each circle. You may cut the radius squares into parts if you need to. Record your data in the table below.
I understood this activity but I'm pretty sure that "Circle 1" on the PDF document is wrong. It does not align with the numbers that are given in the solution. Even the sample picture above shows Circle 1 with 6 shaded squares but the PDF only shows 5. For the chart below, I have included the answer that is shown on the solution page. However, I did not understand the part about how many more squares are needed, even though I used the grid paper for his problem.
I understood this activity but I'm pretty sure that "Circle 1" on the PDF document is wrong. It does not align with the numbers that are given in the solution. Even the sample picture above shows Circle 1 with 6 shaded squares but the PDF only shows 5. For the chart below, I have included the answer that is shown on the solution page. However, I did not understand the part about how many more squares are needed, even though I used the grid paper for his problem.
Problem B6:a. What patterns do you observe in your data?
It is obvious to see that in order to get the radius of the square, you have to square the radius of a circle. In these cases, squaring 6 results in 36, squaring 4 results in 16, and squaring 3 results in 9. I can also make a connection between needed 3 extra radius squares to fill the circle. I connect this to the idea of having a little over 3 diameter lengths to equal the circumference. Or--Pi.
It is obvious to see that in order to get the radius of the square, you have to square the radius of a circle. In these cases, squaring 6 results in 36, squaring 4 results in 16, and squaring 3 results in 9. I can also make a connection between needed 3 extra radius squares to fill the circle. I connect this to the idea of having a little over 3 diameter lengths to equal the circumference. Or--Pi.
b. If you were to estimate the area of any circle in radius
squares, what would you report as the best estimate?
I would say that since you are going to need a little over 3 squares each time, you would want to use π for the best estimate.
Problem B7: Does the activity of determining the number of radius squares it takes to cover a circle provide any insights into the formula for the area of a circle?I would say that since you are going to need a little over 3 squares each time, you would want to use π for the best estimate.
I'm not sure if I completely understand the connection or even if I'm able to put my thoughts into words but I will give it shot.
We know that when using grid paper, you can fit a certain number of the given r^2 squares into the given circle. When finding area of a square you are using r^2. So it makes sense to use π x r^2 to find the area of the circle. You would use multiply by π because you need to calculate the 3 or so extra squares.
We know that when using grid paper, you can fit a certain number of the given r^2 squares into the given circle. When finding area of a square you are using r^2. So it makes sense to use π x r^2 to find the area of the circle. You would use multiply by π because you need to calculate the 3 or so extra squares.
Problems B8-B10
I was not able to answer these questions because I was confused by them. I honestly have never worked with giving circles a scale factor of different numbers and even fractions. I feel like I need a lot more exposure and practice with these concepts before being able to solve them.
I was not able to answer these questions because I was confused by them. I honestly have never worked with giving circles a scale factor of different numbers and even fractions. I feel like I need a lot more exposure and practice with these concepts before being able to solve them.
For Further Consideration...
We have explored numerous areas
throughout this semester. Choose five ideas that you know you will use later in
the classroom and write about them on your blog.
I will say that I have learned a
lot of valuable information from this course that I will undoubtedly take with
me in my future teaching career. While it's hard to pick out the most important things, I have chosen the five most interesting things I learned and experienced.
1) Use of manipulatives
While I have experienced working with certain types of mathematical manipulatives, I have never used some of the ones we worked with from our kits for this course. Things like the pentomino pieces, the tangram puzzle, and that Mira tool (my favorite!) were all very interesting and sometimes helpful items to use. While they helped me in some areas and less in others, I have come to realize that my future students may understand important math concepts when these items are available and taught. I think this is just something to keep in mind.
2) Integration with other subject areas As a teacher, I know time will be a very precious thing--it will not always be on my side. For this reason, I have learned that it is often necessary to integrate math with other subjects to save some time. One module prompted me to think about integrating geometry with history by having students examine patterns in the items made by different cultures. Many of the NCTM articles described the incorporation of math with science and history. The children's literature project allowed me to think about integrating math with language arts and reading. I think this is super important, not only because it engages students, but because there are many great books that encourage children to learn about math.
1) Use of manipulatives
While I have experienced working with certain types of mathematical manipulatives, I have never used some of the ones we worked with from our kits for this course. Things like the pentomino pieces, the tangram puzzle, and that Mira tool (my favorite!) were all very interesting and sometimes helpful items to use. While they helped me in some areas and less in others, I have come to realize that my future students may understand important math concepts when these items are available and taught. I think this is just something to keep in mind.
2) Integration with other subject areas As a teacher, I know time will be a very precious thing--it will not always be on my side. For this reason, I have learned that it is often necessary to integrate math with other subjects to save some time. One module prompted me to think about integrating geometry with history by having students examine patterns in the items made by different cultures. Many of the NCTM articles described the incorporation of math with science and history. The children's literature project allowed me to think about integrating math with language arts and reading. I think this is super important, not only because it engages students, but because there are many great books that encourage children to learn about math.
3) Data collection In the first part of this course, it was interesting to learn about how children go through the data collection process. Many of the articles and videos gave some great ideas to use when teaching this concept to them. It was helpful to learn about the different stages children go through when visualizing and representing data. I now know that it is important to give students plenty of opportunities to see data displayed concretely before introducing them to more abstract ways.
4) Use of technology
It is no secret that we live in such a technology-rich world. I have no doubt that most of the children that enter my classroom will be computer savvy, know how to use the Internet, and will be familiar with using applets on tablets. Many of the modules in this course have shared great examples of mathematical games, applets, and videos children can access to reinforce information they learn in class.
It is no secret that we live in such a technology-rich world. I have no doubt that most of the children that enter my classroom will be computer savvy, know how to use the Internet, and will be familiar with using applets on tablets. Many of the modules in this course have shared great examples of mathematical games, applets, and videos children can access to reinforce information they learn in class.
5) Inquiry-Based instruction and learning
As a visual and hands-on learner, I have always appreciated the fact that some of my teachers used a lot of engaging activities to help me learn and understand information. As a future educator, I hope to give students adequate opportunities to learn in this way. Many of the articles and videos we have watched in this course highlight the use of inquiry-based instruction where students investigate a problem and seek answers using their own ideas and mathematical knowledge. It is clear that using this kind of approach can help make learning math more fun and meaningful for students, especially in the subject of mathematics. I will be sure to remember this.
As a visual and hands-on learner, I have always appreciated the fact that some of my teachers used a lot of engaging activities to help me learn and understand information. As a future educator, I hope to give students adequate opportunities to learn in this way. Many of the articles and videos we have watched in this course highlight the use of inquiry-based instruction where students investigate a problem and seek answers using their own ideas and mathematical knowledge. It is clear that using this kind of approach can help make learning math more fun and meaningful for students, especially in the subject of mathematics. I will be sure to remember this.



















