Wednesday, February 5, 2014

Dilations & Scale Factor Journal entry

This year, I started an interactive journal in my math class.  I have LOVED it.  I can see such a difference in how the kids are understanding.  It allows for them to have a hands-on approach while learning how to take short notes that are to the point.  It is still a learning process, but I am loving the process!

A few years ago, I implemented, "Say NO to Oreos".  WHAT?????  Who could say NO to oreos?  We do this when we learn about scale factor.  The NO stands for New divided by Original.  We start this saying at the beginning of the year, and we use it all year.  In the past, I have always brought in three types of oreos:

  • regular
  • double stuft
  • mini

We go through a lesson in which we start with the regular oreo and dilate it through an enlargement (the two types of dilations were discussed the day before); therefore, the double stuft is created. The students measure the oreos, and we calculate the scale factor used.

We then have the regular oreo and dilate it through a reduction; therefore, the oreo mini is created.  We do more measurements and get that scale factor.

The students have always responded very well to this.   Since I started journaling this year, I created a journal entry, so the kids could put down what they took away from it.

After each situation, we put the oreos down in the journal.  The characteristic of each type of dilation was included.

I created a little pop out which included our saying that we taped to the middle of the page.

The pop out opens up to reveal what the NO stands for.

I love how we were able to keep something from this activity that the kids can go back and look at.  The kids loved to eat the oreos!!

I am excited to see the finished journal!

Happy Dilating!!


  1. Hello, I'm a 7th-grade student and I would like to know what you mean by height of the regular oreo in the first part. I have gotten your PDF and PowerPoint from and wanted to know how you have gotten 1 inch for the height of the regular Oreo in the first part. I am doing a project at school where I have to teach my Math class a lesson that we learned this past year and I chose dilations. When I came across this project, I was delighted by the simplicity, so I just had to do it! Thank you!

    1. Hello Adeliya! First of all, I am most impressed with your writing. It came across as very professional.

      Since regular oreos are still small in height, each student works with a partner. They stack two regular oreos on top of each other. This provides easier numbers to work with. Once everyone has measured the height of the two oreos, we talk about the measurement that was derived. Some measurements will be slightly different. We talk about that since the cookies are made in a factory, they won't all be the same exact amount. So that we all have the same measurement, we use one inch for the height.

      The measuring itself is an added bonus. The main thing we are interested in is getting a measurement, so we can calculate the scale factor.

      Let me know if you have any additional questions. Good luck!