Cut-and-Paste Pi: Pi Post #3

January 17, 2014

cut and paste pi (1)

Click the MORE…tag to reveal this whole post on how to do a cut-n-paste pi

Here’s a hands-on, cut-n-paste  paper project that, hopefully,  puts pi in your hands. This post is 19 photographs long, so, in deference to anyone to whom  seeing that circumference divided by diameter equals 3.14 is inconsequential, I have hidden the bulk of this post under the MORE tag button in this post. If  you want to see the whole project, please click the more button, and I will see you on the other side….

You will want to have  a pencil, a ruler,  a sheet of lined paper,  four crayons, a circular cylinder that fits on the paper, and some tape or glue. My circular object here is a roll of silver tape.
What does Pi look like? A  Hands-on Pi project Step 1

1. Here I’m laying my big roll of silver tape on a line of the paper and marking the lowermost point.

What does Pi look like? A  Hands-on Pi project Step 2

2. Next, the top of circle gets marked. It so happens that this mark lands on a line, but this won’t always be the case!

What does Pi look like? A  Hands-on Pi project Step 33. Use the ruler to make lines across the paper to show the distance between the points. The lower point, which was on a line to start with, will be easy to draw. If the top point didn’t land on a line, lay the ruler on the point and eyeball the ruler so that it is parallel to the lines  of the paper. This is easier than it sounds.  You’ve now delineated across the page length of  the diameter of the circle.

What does Pi look like? A  Hands-on Pi Project Step 4

4. Crayon in four strips of color between the drawn lines.

What does Pi look like? A  Hands-on Pi Project Step 55. Cut out the strips. They can be different widths but the heights should be exactly the same as the diameter measurement.

What does Pi look like? A  Hands-on Pi Project Step 66. Use paste or scotch tape to attach the first strip to the circular cylinder.

What does Pi look like? A  Hands-on Pi Project Step 7

7. Paste or tape the second strip on to the cylinder, making sure that it is right next to the end of the first strip.

What does Pi look like? A  Hands-on Pi Project Step 8

8. Paste or tape the third strip onto the cylinder, again making sure that this strip is exactly lined up with the end of the previous strip.

What does Pi look like? A  Hands-on Pi Project Step 9

9. After gluing down the three strips around the cylinder, notice that there is a small gap between the first and last strips. This is  a .14, or 14%, length of the diameter that we started with.  Now, get ready to make .14 of the original diameter:

What does Pi look like? A  Hands-on Pi Project Step 1010. Note that the full length of the strip is 100% of the diameter.

What does Pi look like? A  Hands-on Pi Project Step 11

11. Fold it in half, and you have .50 of the diameter.

What does Pi look like? A  Hands-on Pi Project Step 12

12. Fold in half again and you’ve got .25 of the diameter.

What does Pi look like? A  Hands-on Pi Project Step 13

13. Here I’ve cut off the .25 diameter piece so its easier to work with.  Fold this in half and….

What does Pi look like? A  Hands-on Pi Project Step 14…and  this half equals between ..12 and .13 of the diameter. But I need a piece that is

. 14, so,…

What does Pi look like? A  Hands-on Pi Project Step 15I will cut this piece just a bit bigger than half!

What does Pi look like? A  Hands-on Pi Project Step 16

The piece I’ve just cut is acceptably close to .14 of the diameter, which I can prove by fitting it into the space between the  strips that are already glued on to my cylinder.

What does Pi look like? A  Hands-on Pi Project Step 17

3.14…

And there it is! it took 3.14 diameters to surround the cylinder.

If you have made it all the way to the end of this post, please let me know what you think. Thank you!!

8 Responses to “Cut-and-Paste Pi: Pi Post #3”


  1. […] the way that the image above visually explains the Pi relationship that I’ve put together a hands-on cut-and-paste activity to really drive the point home. It’s 19 photographs long.  I think it will be a few days […]

    Like

  2. dinasoliman Says:

    This is the kind of thing that young children should be doing in the classroom! How will they know for themselves that the diameter of a circle is the value of pi? Or even know what pi really means for mathematics? Great post, thank you for sharing! Wonderful pictures as well! (I have a younger sister that I will be doing this with! She is 11 years old. :))

    Like

  3. Siri Says:

    Wow! I understand this better than I ever did before! What a fun and very clear way to show this relationship! I love the easy practicality of getting to your .14 measurement at the end. Go, Paula!

    Like

  4. Gregory Says:

    I just found a new unique project that hasn’t been done in our building. I am totally going to share it.
    Love the 4 diameters at the beginning.

    Like


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