# How can proportions be used to make scale drawings of objects accurate?

I love teaching rates, ratios, and proportions because there are so many hands-on projects and activities that students can do.  Scale drawing is one of the sections in this unit that has many ways to be creative.

In the past, I have had students make a scale drawing of my classroom in floor planner.com.  This program allows students to make 2-D and 3-D representations of my room. However, I wanted students to see how a scale drawing worked with paper and pencil.  So I came up with the Mickey Mouse Scale Drawing Activity.  In this project, students had to draw an enlarged version of Mickey Mouse.

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I found a picture of Mickey Mouse on Google images and copied it onto an 8 1/2″ by 11″ piece of graph paper.  Then, I gave students an 11″ by 13″ piece of paper with larger squares on it.  Students had to copy Mickey Mouse box by box.  I explained that it was not an art class on free drawing.  Rather, it was the ability to figure out where each line started and ended in each box.  I chose a picture that had a lot of curves in it so that they could see that it was about using proportions rather than a ruler.  Also, I deliberately chose not to center Mickey Mouse on the original copy so that students would have to figure this out on their own.

At first, students complained that the picture was too difficult to draw.  However, in the end, most students were very impressed with their ability to make Mickey Mouse look almost as good as the original picture.

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Below is the rubric that I created for this assignment.

Lately, I have noticed that my 7th graders do not want to take the time to read the instructions on their own.  They would rather come up to me to find if they completed everything properly. So with this project, we read over the rubric together on the first day that the project was assigned.  After that, if a student came up to me to ask if they were finished or if it looked right or if they were doing it right, I would gently remind them to review the rubric.  In the end, most students followed the instructions well and I was less frustrated because they stopped asking the same questions when they realized my answer was the same – read the rubric.  Hopefully, this carries over to the next project!

# My Version of Sarah Hagan’s Road Trip Project

While studying proportions, I wanted to give my students a real-world application, as well as, a fun activity.  I thought that Day One of  Sarah Hagan’s Pre-Algebra Road Trip Project fit the bill perfectly.  It allowed each student to make choices on which five cities they wanted to visit and it gave them practice in solving proportions using a scale.

As an introduction to the project, we watched this YouTube video explaining the project.  The teacher in the video did a great job covering the technical aspects of the project.  I think my students listened more intently to the teacher in the video than if I stood up in front of the class and explained it.

Since I wanted students to be able to work independently and for them to read instructions without constantly raising their hand to ask me what else they needed to do, I made a step-by-step instructions sheet to go with the project.

For easier grading purposes, I wanted all of the work to be done on one sheet, so I combined some of the steps and came up with this handout.  However, if the work space was not big enough, I allowed students to complete their work on a separate piece of lined paper.

I’m not sure if I am alone on this, but I have a hard time grading solely using a rubric.  It just seems so harsh.  And I don’t know what to do with some of the miscellaneous items that I feel are important, but don’t seem to fit in one of the categories.  So, I improvised and put a few such categories at the bottom of the rubric that I felt were valuable, but only worth a point or two.

Finally,  I wanted students to realize that because they were drawing straight lines between cities and not using actual roads to come up with the distances, their total mileage would probably not be an accurate measurement of their road trip.  As a result, I thought it would be fun for students to go on the Internet and find the actual mileage their road trip would be and then find the difference between the two mileage amounts.

I have done this for two years now and both times I was amazed at how many student forget how to use a ruler, how to estimate to the nearest quarter of an inch, how to multiply with decimals or fractions (even though we covered both of these concepts already), and how to find the difference between two numbers (subtract, not add).  It’s as if students put each unit that we’ve covered in a separate box and close the lid when the chapter test is completed.  Keeping that information available to use at any given moment is a challenge.  It reminded me that spiral review like this is so important!

Overall, I loved this project!  Thank you, Sarah Hagan!!