How are standing waves different from travelling waves?

Standing waves are different from travelling waves because they do not transfer energy from one place to another.

In more detail, standing waves, also known as stationary waves, are waves that appear to be standing still. They are formed when two waves of the same frequency and amplitude travelling in opposite directions interfere with each other. This interference creates points of maximum amplitude, known as antinodes, and points of zero amplitude, known as nodes. The wave pattern remains in a fixed position, hence the name 'standing wave'. For more insights, you might find it helpful to read about the formation of standing waves.

On the other hand, travelling waves, also known as progressive waves, are waves that transfer energy from one place to another. They are characterised by peaks and troughs that move in one direction. The energy of a travelling wave is transported from the source of the wave to its surroundings. Examples of travelling waves include sound waves, light waves, and water waves. To better understand the diversity of wave types, including travelling waves, the page on types of waves provides detailed explanations.

The key difference between standing waves and travelling waves lies in their energy transfer. While standing waves do not transfer energy from one place to another, travelling waves do. This is because in standing waves, the energy is trapped in one location, oscillating back and forth between the nodes and antinodes. In contrast, in travelling waves, the energy is continuously moving forward, carrying the wave's energy with it.

Furthermore, the formation of standing waves requires specific conditions, such as the correct frequency and a medium with fixed boundaries. This is why standing waves are often observed in musical instruments, where the strings or air columns provide the necessary conditions. Travelling waves, however, can form and propagate under a wider range of conditions.

IB Physics Tutor Summary: Standing waves and travelling waves differ mainly in how they handle energy. Standing waves seem to stay in one spot, creating nodes and antinodes without moving energy around. In contrast, travelling waves move energy from one place to another, like the ripples in a pond. Standing waves need specific conditions to form, unlike travelling waves, which can happen in many settings.