How To Describe 3D Shapes

Three-dimensional, or 3D shapes, are shapes that take up space. They have three dimensions. Length, width, and height. The world is made up of 3D shapes. They are all the things we can hold. Your book is a 3D shape. So is your soccer ball. As well as your birthday presents. Can you see how they each take up space? There are some features that are common across three-dimensional shapes. These features include faces, edges, and corners. The flat surfaces of a shape are called faces. No, not that type of face. The edge of a 3D shape is the line where two of its surfaces meet. And the corner is where two or more edges meet. A corner can also be called a vertex. The faces of 3D shapes often contain 2D shapes that you may already know. Maybe you can recognize some of these 2D shapes as we go through a few examples. Here are some three-dimensional shapes and their features. This shape is a cube. A cube has six faces that are identical. Twelve edges and eight corners. All of the faces, edges, and corners are the same size and length. Can you see how each face of the cube is a square? This shape is called a rectangular prism. A rectangular prism has six faces, twelve edges, and eight corners. It's very similar to the cube, except instead of all the faces being squares, they're rectangles. The opposite faces of a rectangular prism are always the same size. This shape is a triangular prism. A triangular prism has five faces, nine edges, and six corners. Triangular prisms have two faces that are triangles and three faces that are rectangles. The two triangle faces are always the same size. However, some 3D shapes have more than just flat surfaces. Some have curved surfaces, but we don't call them faces because faces are always flat. This shape is called a cylinder. A cylinder has two circles on each end that are the same size, with a tube in the middle. It has two flat faces and one curved surface. The cylinder also has two edges, but no corners. Remember, a corner is where two or more edges meet. In a cylinder, there are no corners because its two edges do not meet. This is a cone. Not an ice cream cone, unfortunately, but it is the same shape. A cone has a circle at its base and a point at the other end. It has one flat face, one curved surface, one edge around its base, but no corners. This unique shape is a sphere. It's perfectly round, just like a ball. This means it has no flat faces, no edges, and no corners. Just one curved surface. How unique is that? That's what makes a sphere the perfect shape for a ball. It rolls around easily in any direction and you can kick it without banging your toe on a sharp corner. Now that you know some three-dimensional shapes, perhaps you can spot a few examples of them in your classroom or outside in the playground.