Solids and Nets, Part 1
- Author:
- Mike Hodapp
Hello Geometry! Welcome to the 3rd dimension! In the next two lessons we'll be doing some exploration of solids and nets. Solids are three-dimensional shapes that are.. well.. solid. They have many interesting properties, but the two that we'll explore first are surface area and volume. Surface area is exactly what it sounds like: the sum of the area covered by the outside of a solid. Volume is a measure of all of the 3-D space contained within a solid.
One way that we can better understand solids is by creating a net. Imagine that you have a cardboard box, and you cut the tape and some of the corners so that you can lay the cardboard flat on the ground, in a just a single layer. A net is the same idea. If we take all of the sides of a solid and fold them down into a flat 2-D representation, we've created a net. A net helps us understand the surface area of solids and how they're constructed.
Take a look at the app below. There are three parts to it: a purple square on the left, a brown cube on the right, and a blue net on the right. Notice that you can play with the app:
- You can move points A and B to change the size of the square and rotate it.
- You can rotate the graph of the cube and net on the right to see them from different perspectives.