Final answer:
The third dimension adds depth to the two-dimensional height and width, allowing us to perceive space more realistically, like in 3-D movies or in mapping galaxies. It also plays a role in physical properties like the deformation of strings in physics.
Step-by-step explanation:
The "third string" dimension typically refers to the third dimension in a spatial context. In physics, particularly when discussing string theory, there's a reference to additional dimensions beyond the familiar three. However, in more commonplace situations, such as mapping the universe or experiencing a 3-D movie, the third dimension provides depth beyond the two-dimensional height and width. For example, mapping galaxies requires understanding their three-dimensional placement in space, not just their location across the night sky. Also, when you watch a 3-D movie with special glasses, the images acquire an additional dimension of depth, making them appear more realistic and tangible.
Another example in physics can be understood by looking at the deformation of guitar strings under force. Different strings made of various materials will deform differently under the same force, revealing the importance of considering the material characteristics, which contribute to how they occupy three-dimensional space.