Balance on a scale is when both pans of the scale are equal in weight.
Visual balance in interior design, can be expressed in many scenarios. One way is to use repetition. This can be done by placing the same object on one side of a room and have it mirrored on the other side. This can be seen in the photo below. You can see that the topiary, chest and arm chair are all mirrored on either side of the fireplace. This type of decor creates a formal atmosphere because it is very organized and predictable.
Another way to balance a room is to use dissimilar objects. The next picture shows a large white sofa upholstered in cotton on one side of the room. On the opposite corner is a black leather chair and ottoman. Visually, although the sofa is much bigger in scale, the color and fabric make it look lighter compared to the smaller black leather chair and ottoman combined. Although the sofa and chair are different in design, shape and size, with the simple use of color, fabric and material creates a visual balance, so the space feels comfortable. This unpredictable balance creates a more casual environment.
With these principles in mind, try putting together your own decor. Maybe you can find something tall like a glass vase and place it next to a small metal item. Think about visual weight when you create your own unique composition. What can you come up with?