Friday, August 5, 2011

Ellipse & Rhombus Masquerading as Oval & Diamond

There are two shapes with which I have a beef. Oval and Diamond. Maria Montessori did not take issue or have confusion about these shapes, and neither should you. Now, if we could just tell American curriculum writers and Mickey Mouse and the people who made my Target shapes puzzle, we'd be all set.
This is something that has bothered me ever since my high school geometry teacher tried to teach me how to do graphing problems involving an ellipse. And e-what? Had I been able to continue my Montessori education through the elementary years, I would have known what an ellipse was. I would have had that picture and name in my mind, having a full understanding of what an ellipse looked like, felt like, etc. Unfortunately, I was told the wrong name in school for a decade.
Look closely at the picture. What are these shapes?



Surely, they are not both called the same thing! The one on the left is an oval. Did you get that one right? The Latin ovalis means egg-shaped and the Greek ovum means egg. Please tell me you see an egg shape.
Now look at the shape on the right. Oval? Heck, no! That's an ellipse! Do not argue with me about it too being egg-shaped. Maria Montessori and dictionary.com have spoken.

Next, take a look at these two shapes:



The one on the left is not a diamond. It's a rhombus. The Latin and Greek won't really help you remember this one, but know that a parallelogram with four equal sides is a rhombus as long as it's not a square. Okay? So what the heck is that shape on the right? A diamond? No. It's a square, silly! Maria Montessori didn't have a geometric shape called a diamond, and I'm thinking, neither should you.
So, if you have the opportunity to purchase a Circo shapes puzzle or any other mislabeled shape puzzle, I suggest the following corrections:



And just for fun, what the heck are these?

2 comments:

  1. Hi feel your fustration my three year old is fascinated with shapes .. and is learning about polygons prisms what the three dimensional version of flat shapes. So had to learn with him and the amount of people who try to correct him when he explains "it's not a oval it's an ellipse" is staggering. Granted I might of been on of them but you can clearly see he has obviously learnt it so must know.. but people are set in their ways and feel they know best. So suprised that this confusion could be allowed to be taught

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  2. The left one is a curvilinear triangle, and the right one is a quatrefoil.

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