Why does waves move

By Alison George. There are many types of waves flowing across the oceans, from small ripples to huge walls of water, 30 metres high peak-to-trough.

They are mainly caused by winds, and, if unimpeded, can travel for thousands of kilometres. Waves occur when the force of the wind blows over surface water, transferring its energy and causing the water to move in a circular motion.

The rise and fall of water molecules creates a wave that moves in the direction of the wind. The wave transports energy, not water. At this point, the top of the wave travels so much faster than the bottom of the wave that top of the wave begins to spill over and fall down the front surface. This is called a breaking wave. A breaking wave occurs when one of three things happen:. In some ways a breaking wave is similar to what happens when a person trips and falls.

As a person walks normally, their feet and head are traveling forward at the same rate. If their foot catches on the ground, then the bottom part of their body is slowed by friction, while the top part continues at a faster speed see Fig. The transition of a wave from a deep-water wave to a shallow-water breaking wave is shown in Fig.

Terms relating to wave depth a described in detail in Table 4. Deep-water waves include all wind-generated waves moving across the open ocean. Transitional waves are often wind-generated waves that have moved into shallower water. Shallow-water waves include wind-generated waves that have moved into shallow, nearshore areas, tsunamis seismic waves generated by disturbances in the ocean floor, and tide waves generated by the gravitational attraction of the sun and moon.

Breaking shallow-water waves are unstable shallow-water waves. Breaking unstable deep-water waves are waves that begin to break when the seas are confused waves from mixed directions or when the wind blows the crests off waves, forming whitecaps. Use a long wave tank to create and observe the differences between deep-water, transitional, and shallow-water waves. This document may be freely reproduced and distributed for non-profit educational purposes.

Skip to main content. Search form Search. Join The Community Request new password. Main menu About this Site Table of Contents. Wave Energy and Wave Changes with Depth. NGSS Performance Expectations: MS-PS Use mathematical representations to describe a simple model for waves that includes how the amplitude of a wave is related to the energy in a wave.

HS-PS Use mathematical representations to support a claim regarding relationships among the frequency, wavelength, and speed of waves traveling in various media. The content and activities in this topic will work towards building an understanding of how waves move through water and how the orbital motion of water particles in waves causes them to break on shore.

Wave Energy Many forms of energy are carried in heat, light, sound, and water waves. After a review none of the projects were selected to progress further and, as of , EECA believe that the abundance of cheaper renewable energy resources in New Zealand makes it unlikely marine energy will contribute to the national grid in the foreseeable future.

Investigations into harnessing the energy of ocean waves continues in other countries. From to , as part of a Sustainable Seas Innovation Fund project, NIWA investigated whether generating electricity from the strong tidal currents within the Cook Strait would be viable for Aotearoa. To find out more, see Energy from tidal currents — Kick-starting a new marine industry with huge potential from NIWA's website. Use a Mexican wave to demonstrate how waves transfer energy and to help your students visualise the wave behaviours of reflection, constructive interference and shoaling.

Use an interactive or paper-based Venn diagram to illustrate the key similarities and differences between tsunami waves and surf waves. Explore more about waves, such as sound and energy by browsing the resources under our waves concept. In NIWA ran a webinar: A step closer to a future powered by tidal current energy , in which the results of the Energy from tidal currents project are presented. This project investigated the viability of generation electricity from the strong tidal currents within Cook Strait.

Find out more about using waves as an energy source in this Wikipedia article. Add to collection. In sound waves, energy is transferred through vibration of air particles or particles of a solid through which the sound travels. In water waves, energy is transferred through the vibration of the water particles. Activity ideas Use a Mexican wave to demonstrate how waves transfer energy and to help your students visualise the wave behaviours of reflection, constructive interference and shoaling.