# Teaching Three-Dimensional

This semester, we have spent a great deal of time talking about methods to teach geometry. We mainly worked with two-dimensional shapes and it has made me think of more effective ways to teach three-dimensional shapes. In my own elementary experience, I remember being handed various objects and associating them with the shapes I had known all along: square, rectangle, triangle, etc. I find it very interesting that when we search around the classroom for examples of shapes, we often refer to them as if they are two-dimensional. I recall looking at objects like a basketball and concluding that it is a circle. As a class we talked about situations where teachers only present shapes such as triangles in one format and becoming unrecognizable when it is rotated. So, why does it seem common to call three-dimensional objects the names of two-dimensional shapes?

I found two particularly interesting activities on Nrich.maths.org. One provides students with an opportunity to observe properties of different 3D shapes. Students are given various blocks and after the chance to play and observe, they can be asked questions like, which of these towers will collapse?

I predict that it would be great as a teacher to witness how students come to conclusions about each shape. I also think that it would be worthwhile to come together as a class to share characteristics that they noticed. I have noticed in my classroom experience so far that 3D shapes almost seem overlooked. Three-dimensional shapes can be incorporated into measurement so that students can determine the differences between 2D and 3D. Volume and surface area are vastly different calculations that area and perimeter. I believe that it is important for lower elementary teachers to set students up for success by providing with more experiences with three-dimensional shapes.

The second activity that I found on Nrich related two-dimensional and three-dimensional object by using shadows. Students are presented with a square, circle, triangle, and rectangle. They are asked what objects on a playground would form that shadow.

I find the relationship between two-dimension and three-dimension fairly interesting. I would consider myself a visual learner and making connections to tangible objects is important to my ability to learn math. I believe that more time spent working with three-dimensional objects would give students a better understanding of volume vs. area.

1. · April 6, 2016

I definitely agree that 3D shapes do get passed by. Sometimes because the school can’t afford them which is sad and sometimes because it won’t dawn on that teacher because they don’t learn that way. I think that adding 3D shapes would add lots of great possibilities to the classroom. In your own classroom when would you use them?? The whole time you teach about shapes? Only when they are first learning? At the end?

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2. · April 6, 2016

Brittany, I appreciate the question. I think that I would teach two-dimensional shapes first, as it is typically taught. However, I would introduce three-dimensional shapes very shortly after. I think it is important that students can identify both in and out of the classroom. I would continue to use them the whole rest of the time that I would be teaching shapes, however I would not teach about volume until developmentally appropriate.

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3. · April 11, 2016

Volume formulas don’t come typically until middle school, except for rectangular prisms.

Kids are definitely interested in three dimensions, and that curiosity helps engagement. The goal is the same as for 2-dimensional: observe a variety and move towards recognizing properties. Silhouette, face shapes, construction, classes, vertices, edges, etc. What you experienced in primary is sadly typical.

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5Cs 5

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