When you begin drawing, the first few shapes that you draw consist of one of these – circle, square, triangle, or rectangle. When making these drawings, you are marking only the length and breadth of the shape. Thus, these are called two-dimensional or 2-D shapes.

In real life, however, objects have length, breadth, and width. For example, consider the shape of your favourite chocolate bar. It has all three dimensions, isn’t it? Or think of the cricket ball you use, when playing with friends. It occupies some space and has three dimensions. Such shapes are referred to as three-dimensional or 3-D shapes.

If you observe carefully, every 3-D shape has multiple 2-D shapes when you look at it from different sides. We will look at this in a little more detail as it will help us understand visualising solid shapes’ class 8 maths chapter much better. But before that, let’s see a few definitions.

Every 3-D shape or solid shape as it is called has a few common elements. Here, we take a look at what these common elements are and how they can be defined. These will help us understand the class 8 visualising solid shapes chapter easily.

•  Faces – When we look at a solid shape from one side, we see a 2-D shape, since we are not seeing the third dimension. These   2-D shapes that combine to make up a solid shape are called faces. This is one of the most important definitions when   studying the visualising solid shapes class 8 chapter.

• Edges – The line segment formed where two faces of a solid shape cross each other is called an edge. Every three-dimensional shape can have one or more than one edge.

• Vertices (Vertex) – The edges of a solid shape meet at points, which are known as vertices. For some shapes like the cone or prism, there may be only one point where the edges meet. This is called a vertex.

• Net – You learned earlier that a three-dimensional shape is formed with the help of multiple two-dimensional shapes that are known as faces. This can also be imagined as if the two-dimensional shapes are being folded to create a 3-D shape. If we unfold a 3-D shape into all the 2-D shapes that make it up and lay them flat, the pattern we obtain is called a net.

With the basic definitions clear to us, now look at a few examples. Consider these shapes carefully and find out the number of faces, edges, and vertices in each of these shapes.

Example 1: Ice-cream Bar: You have seen the big ice-cream block that is available for families. Can you identify the solid shape of this bar?

It is a cuboid. The bar has 6 faces (each either a rectangle or a square), 12 edges, and 8 vertices.

Example 2: Water Bottle: The water bottle that you use at home is generally cylindrical. It has top and bottom faces that look like circles and has a height. Thus, the bottle has 2 faces, but no edges or vertices.

Example 3: Dice: Have you played a board game? Then you must have seen a dice. You roll the dice to get a number from 1 to 6 that is marked on the faces of the dice. What shape is a dice? It is a cube. A standard dice has 6 faces, 12 edges, and 8 vertices.

The number of faces, vertices, and edges for a cube may be the same as a cuboid. But there is a crucial difference between the two. All the edges of a cuboid must be of the same length, whereas this is not true for a cuboid.

What are some other solid shapes that you see every day? How about the wall clock, the chair on which you sit to stud, or the book that you read? What shapes are these objects? Identifying the right shapes along with the faces, vertices, and edges is the first step in visualising solid shapes class 8 chapter.

When you look at a two-dimensional shape, it remains the same irrespective of where you are looking from. However, as you know, solid shapes take up space. Hence, if you look at a solid shape from a different direction, it may appear different. The shape you see will depend on the face of the shape you are looking at.

Let us understand this with an example. Look at your bookshelf. What shape is it? A regular bookshelf is a cuboid in shape. There are 6 sides to it, with the top and bottom being smaller rectangles. Similarly, the sides of the shelf will be rectangles, yet their size will change as compared to the front and back of the shelf.

Now imagine, you are looking at this shelf from the front. What is the shape and size that you see? Next, move to one side of the shelf and look at it from there. Do the shape and size remain the same? Suppose you climb onto a chair and look at the top of the bookshelf from above. Are the shapes and sizes different? Most likely the front view, the side view, and the top view of your shelf will be different from each other. Yet, they are all rectangles. What happens when you look at the cylindrical shape of a bottle from the side view or the top view?

The difference in the different views is the reason we need to understand how to visualize solid shapes. The visualising solid shapes class 8 chapter helps you learn how to do this. Let us now understand a very important concept that will help us – the concept of Perspective.

You saw in the previous section that if you view the same solid shape from different sides, you may end up looking at different two-dimensional shapes. These different views are called perspectives. Thus, if you are looking at a bookshelf from the front and your sibling is looking at it from the side, you both are looking at it from different perspectives.

You must have seen a map – of your locality, city or even the country. Let us take an example of your school. If you and your friend are asked to draw the map of your school playground, will both the maps be the same? Not necessarily. You may draw the map from your perspective, whereas your friend will draw it from their perspective.

Your map may represent a longer distance, for example, 10 m in 1 cm of the map. Your friend may choose to represent 1 m by 1 cm in their map. This one small difference can make a lot of difference to the maps that you both come up with. For a map to be useful, however, it has to be free of perspective. No one view should be given more importance than the other. The shape and sizes of objects and distances between them must be standardized, for the map to be helpful.

 

In this chapter, you saw the difference between 2-D and 3-D shapes. You also learned that 3-dimensional shapes occupy space and volume. This leads to different perspectives, depending on where the solid shape is viewed from. You also learned the basic definitions that help you define a solid shape and visualize it.

The concepts presented here are good for basic understanding. But if you want to explore more with the help of numerous examples, head over to the MSVGo App. There you can find visual illustrations and educational videos that will help you in understanding the visualising solid shapes class 8 chapter much better. You can also solve the sample problems to get a better understanding of the concept. Go ahead champ, explore the world around you. Identify the solid shapes and visualize how they will appear from different perspectives.