Today, we started a new unit on Geometry. Specifically, we’re looking at finding the area of triangles, quadrilaterals, and irregular shapes, and the surface area and volume of pyramids and prisms. In my experience, kids can handle the 2D shapes pretty well, as long as they can see how to break apart irregular shapes. It’s the 3D shapes that start to give them a hard time, and even here, volume doesn’t seem to be as much of an issue as surface area. So, in an effort to remedy this, most teachers turn to paper nets (3D models of a shape) to help kids see all of the sides of shape, so that it all starts to come together in their head.

Yeah. Have you ever actually tried to make nets with the kids? Even 6th graders have a hard time cutting them out, a harder time folding the paper on the lines, and taping/gluing the sides together is a joke. A. JOKE. Glue everywhere, 3 rolls of tape used up (on the nets and on people’s faces [“Mrs. K, does this face scare you?”], as I learned last year), an entire block of time gone making the stupid things, and yet, the kids are no closer to understanding what the heck is going on when you’re trying to find surface area.

A fellow 6th grade teacher in my building, Aaron, showed me this app on his phone a few weeks ago, and I knew that this would be a great way to show the nets without taking 90 minutes to put one together. The app is called “Solids Elementary HD” and it provides math teachers and students with tons of 3D shapes to look at! Solids costs $1.99, but after playing with it for an hour a little while this afternoon, I’m über-psyched to use it in class. It’s got a very clean and realistic look, is easy to use, and allows you to highlight and color different parts of the shape. You can use it on a computer (which is how I’m using it this year) or on an iPhone (I haven’t checked on its iPad abilities — I would hope that it works there too!)

You can choose from the above 3D shapes.
You can choose from the above types of 3D shapes.

Once you choose your shape, the fun can begin!

The different shapes are on the bottom row. Just click on one in the app to select it for a closer look.
The different shapes are on the bottom row. Just click on one in the app to select it for a closer look.
A common shape that my kids will use during this unit.
A common shape that my kids will use during this unit.

You can change the transparency of the shape — good for kids to see! I also really love that you can also highlight the vertices and edges of the shapes.

Vertices are marked in red.
Vertices are marked in red.
Edges are highlighted in yellow.
Edges are highlighted in yellow.

The COOLEST part? You can open and close the shape! Opening and closing the shape is awesome, because kids can see how the whole thing comes together! It can be folded and unfolded using the sliding scale on the right. You can also rotate the shape, which allows kids to see the shape from all angles.

Screen Shot 2013-01-06 at 4.53.39 PM
The opened rectangular prism. In this shot, the shape s being rotated, which is where the circles in the back come into play. They disappear once the shape is where you want it.

Solids rotated

The faces of the shape can be color-coded, too!

I like having all of the faces with the same dimensions have the same color, but it can be left to you and your kiddos!
I like having all of the faces with the same dimensions have the same color, but it can be left to you and your kiddos!

The shape can be partially opened -- use the slider to fold and unfold the net.

Pretty excited about this! Obviously, the paper nets can still be used — perhaps at home…? 😉

Mrs. K

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