A dune is a mound of sand formed by the wind, usually along the beach or in a desert. Dunes form when wind blows sand into a sheltered area behind an obstacle. Dunes grow as grains of sand accumulate.

These dunes form when complex wind patterns alternate direction and change the way sand is piled onto the dune. Weathering is the physical and/or chemical breakdown of surfaces due to wind, water, or ice. Erosion is the process of moving the broken down material from one place to another via wind, water, or gravity.

In deserts, wind picks up small particles and leaves behind larger rocks to form desert pavement. Moving sand may sand blast rocks and other features to create ventifacts. The sand is transported until it is deposited in a sand dune.

Wind Deposition Wind erosion and deposition may form sand dunes and loess deposits. When the wind strikes an obstacle, the result is usually a sand dune. Sand dunes can be seen on beaches and in deserts where windblown sediment has built up.

These broken pieces of rock are called sediments. The word “Sedimentary” comes from the root word “Sediment”.

A beach is part of a shoreline that is made of deposited sediment. 2. Answers include: wind (produces waves, which erode and add to the shore), waves 3. The sand can have different colors, which come from the kind of rock it is made from.

Types of depositional environments

• Alluvial – type of Fluvial deposite.
• Aeolian – Processes due to wind activity.
• Fluvial – processes due to moving water, mainly streams.
• Lacustrine – processes due to moving water, mainly lakes.

What is the main drawback of seawalls? As waves enter the coastal zone, wavelengths shorten and wave heights increase. What adverse effect do groins and jetties both have on coastal erosion?

Water molecules are displaced towards the shore and breakers form. Shorelines tend to be irregular in shape and the waves generally approach the shore at some angle other than 90 degrees. The net effect is for the waves to bend (refraction) so that the wave hits the beach nearly parallel to the shoreline.

When waves approach the beach at an angle, the part of the wave that reaches shallow water earliest slows down the most, allowing the part of the wave that is farther offshore to catch up. In this way the wave is refracted (bent) so that it crashes on the shore more nearly parallel to the shore.

As the wave moves into increasingly shallow water, the bottom of the wave decreases speed. There comes a point where the top of the wave overtakes it and starts to spill forward — the wave starts to break. We’re surfing! In general a wave will start to break when it reaches a water depth of 1.3 times the wave height.

Notes: Surging Breaker – waves that do not break in the traditional sense. This wave starts as a plunging, then the wave catches up with the crest, and the breaker surges up the beach face as a wall of water (with the wave crest and base traveling at the same speed).

shorelines

Surging waves are the result of long period swells. As a result, the wave is slow, the faces are smooth and oblique, and the crest barely exists. These waves may not break at all. Breaking waves have a deep trough; surging waves do not.

When deep-water waves move into shallow water, they change into breaking waves. Because of the friction of the deeper part of the wave with particles on the bottom, the top of the wave begins to move faster than the deeper parts of the wave.

In shallower water near the coast, waves slow down because of the force exerted on them by the seabed. Even if waves are coming in from deep water at an angle to the beach, the move to shallower water means that the waves will slow down and curve around (refract) so they are more parallel as the surf hits the beach.

Refraction of waves involves a change in the direction of waves as they pass from one medium to another. So as water waves are transmitted from deep water into shallow water, the speed decreases, the wavelength decreases, and the direction changes.

As a wave enters shallow water, wave height increases and wavelength de- creases. As the ratio of wave height to wavelength, called wave steepness, increases, the wave becomes less stable.

Answer. Waves are created by energy passingthrough water, causing it to move in a circular motion. Wind-driven waves, or surfacewaves, are created by the friction between wind and surface water. As wind blows across the surface of the ocean or a lake, the continual disturbance creates a wave crest.

Answer: the frequency of the wave. We see that frequency is inversely proportional to the period: therefore, if the period decreases, the frequency of the wave increases.

Reflection occurs when a wave strikes an object and bounces off of it.

Frequency of the wave, v=1T=10.002=500Hz.

Light, heat, radio, and similar types of energy are carried by a variety of waves in the ELECTROMAGNETIC SPECTRUM. Some energy waves need a medium, such as water or air, through which to travel. The medium moves back and forth as waves carry energy through it, but it does not actually travel along with the wave.

Three ways that waves may interact with matter are reflection, refraction, and diffraction. Reflection occurs when waves bounce back from a surface that they cannot pass through.

If the two sound waves that collide are exactly in phase with each other they add together and produce a sound wave that is twice as loud. If they are exactly (180°) out of phase, they cancel each other out and the result is silence.

When a wave passes the edge of an object or passes through an opening, the wave bends. That is called DIFFRACTION. A wave also bends when it passes from one medium to another at an angle. That is called REFRACTION.

When two or more waves arrive at the same point, they superimpose themselves on one another. More specifically, the disturbances of waves are superimposed when they come together—a phenomenon called superposition. Each disturbance corresponds to a force, and forces add.

When two waves occupy the same point, superposition occurs. Superposition results in adding the two waves together. Constructive interference is when two waves superimpose and the resulting wave has a higher amplitude than the previous waves.

Two sound waves of the same frequency that are perfectly aligned have a phase difference of 0 and are said to be “in phase.” Two waves that are in phase add to produce a sound wave with an amplitude equal to the sum of the amplitudes of the two waves.