Math Journal Sundays - Circumference and Time

10 February 2013
We were busy in our interactive math journals this week, so I have two fun entries to share with you today:  circumference and time (elapsed time and the 24 hour clock).

Late last week we started to look at circumference.  I started the lesson by reading the story, Sir Cumference and the Dragon of Pi.  If you haven't read any books in the Sir Cumference series, you HAVE to!  They are perfect for upper elementary and middle school students, and such a great way to integrate reading into math.  My students love these books.  (I've included a link to Amazon below so you can check it out).  

We then started our journal entry.  To make the circles, I gave the students two different strips of paper.  They taped the strips together to make circles, then dipped the circles in paint to make two different circle stamps on their paper.  After the paint had dried, they taped the strips to their journals.

We measured the diameter of the circles, then measured the length of the strips (which we discussed would be the circumference of the circle).  On their own, the students figured out that circumference is about 3x the diameter of a circle (in our curriculum, "pi" isn't discussed until grade 7).  We added this information, our "big idea" under a sticky note on our journal page. 

In our "proof", I asked the students to draw a different circle, and find the diameter and circumference of the circle.  For our reflection, I used the Math Reflection Fans and chose the question, "What other math can you connect this to".  This entry was so much fun - and the students couldn't believe we were actually using paint in math class!

Now, on to time ... I wanted to combine two of our expectations, elapsed time and the 24-hour clock, so the students would have something to refer to for our upcoming lessons.

We made a clock for our math journals for this entry.  We used small paper plates for our clocks, but if you don't have any paper plates, you could easily use paper circles instead.  We divided our circle into twelfths (snuck a little bit of fractions in there), and labelled our clocks (hours and minutes).  We then cut a small strip at the edge of each section so we could fold over the flaps.  On the back of the flaps, we wrote the 24-hour times.  We made hour and minute hands, and attached them to the clock with a brass fastener.  
With our clocks, we practiced telling the time with the 24-hour clock, and then I gave them some elapsed time questions (I have more lessons on both planned for this week).  For the proof, I asked them to create and solve a problem related to elapsed time, and I challenged them to answer in both analog time and 24 hour time (most only answered one way, though).  I used my reflection fans again to choose a reflection question - I made it easy on them today and asked them, "When could you use this math outside of school?  Explain."  

Well, that's it for today ... I've got to get back to my report cards.  Wish me luck!!!



  1. I LOVE the little Big Idea sticky note. The kids must have loved it as well!

    Fab ideas, as always :)

    Teaching in Room 6

  2. What a great way to show circumference. Paint! So smart, Jen. I love the elapsed time clocks, too. Pinning both for later :)

  3. I absolutely love this book and the others by this author!

  4. If only my classes were trained to do this. We can't even use a highlighter without everyone throwing fits (6th grade) and WHITEBOARDS and dry erase markers... by golly it's just drawing time! Very jealous and would LOVE to implement this... one day.

  5. I used your interactive journal idea with a group of kids recently, Jen, and I'm delighted with the results. They were bummed about having to work a little harder on some skills that they just don't have down yet (yes, we're gearing up for testing time in PA!) and on impulse, I decided to have them write down some of the ideas and their thoughts in their journals. Somehow, it's just changed the way they think about their work. Thank you for the great idea! I'm writing a blog about it tonight and posting pictures. You get the credit!


  6. HI! I wanted to say thank you for your wonderful ideas. I blogged about you on my circumference lesson. Thought you might want to check it out.


    1. Hi Jen, I purchased your math journal recently, I homeschool my 5th grade son. I left an assignment for him to do with my husband yesterday and my husband pointed out that your example is incorrect on page 82, "The Metric Staircase." I didn't even notice and would've continued teaching it to my son. I just thought you might want to repost a correct example Kilo=1000, not 0.001; Milli= 0.001, not 1000. He found a great website for reference Take care, Camie

  7. I love this entry!!! I love the Sir Circumference series. Great addition to your notebook!

  8. I love these Interactive Math Journals!! I love this entry! I hope to be able to do something like this for my students in the future.

  9. I love the Sir Cumference series. It is so much fun for kids (and adults!) and they do a great job of explaining different math topics. I hope they keep writing them!

  10. I absolutely love the way that you teach! AMAZING!You can tell the hard work and dedication you put into your teaching! This is what quality is about!!!
    My question is what do you have the students write for their reflection piece? Do you have them write about how well they feel they grasp the concept? Also do you have them write a reflection piece for reading?
    Thanks so much!