When a wind begins to blow across a flat body of water ripples form almost immediately, then wavelets, and finally nearly fully developed waves, having almost definite wave lengths and shapes. Surface waves will also form, during calm wind, where opposing currents meet. This is known as current rips and can be dangerous for small or overloaded boats.
A good estimate of the wind speed can be obtained by observing its effect on the water. For example, at 5 knots only small wavelets can be observed. A 10 knot wind speed will produce a few whitecaps. At 15 knots whitecaps can be seen up to 30% of the area. At 20 knots whitecaps can be seen up
to 60% of the area. At 30 knots whitecaps and spray can be seen all over and foam from the breakers begins to form. At 40 knots streaks of foam can easily be seen. At 50 knots visibility is reduced and the sea begins to take on a white appearance from all the foam. Current directions and speed will greatly affect the areas covered by spray and breakers.
Factors Affecting Wave Heights:
1. Wind.
2. Wind duration.
3. Length and width of wind fetch. (This is the distance over the water in which the wind blows in nearly the same direction.)
4. Depth of the water.
5. Direction and speed of the current.
6. Rate of precipitation.
7. Air temperature.
8. Amounts of flotsam, ice, or seaweed in the fetch area.
1. How high will the waves get? Maximum wave heights (in feet) will not get any higher than * the wind speed in knots. This is correct over 90% of the time. Note: Wave height begins to increase when the depth of the water is less than or equal to 1/4 of the wavelength because the wave starts to touch the sea floor.
2. What is the difference between waves and swells? Waves occur where the wind is blowing. Swells are waves that have moved away from the wind generating area and frequently give warnings of an approaching storm.
3. What is the significant wave height? Significant wave height (SWH) is the average height of 1/3 of the highest waves, or the height of the waves an observer is most likely to report. The significant wave height is used in the marine forecasts.
Table 1.Wave heights in relationship to the significant wave height (SWH)
Most frequent wave height .5 x SWH
of tides. High - water heights vary from 22 to 28 feet and low - water heights
Figure 6 - How longshore drift works (Brief). Source: Classwork image (originally from Google images)
Rachel begins by stating that when tides or waves occur in the ocean they don’t just effect the surface but also the deepest levels of the water. How would you know for a fact that the wave currents run deeper than just the surface? Proof given by her illustrates
To Test if Longshore Drift is Taking Place Along Deal Beach on the Day of Our Visit
An aeroplane flies about 400-500 metres above the water at a speed of approximately 60 - 70 m/s. Then the aircraft will send out a pulse which is moderately reflected off the surface of the water and moderately broadcasted into the water and reflected off the ocean floor, as a result two pulses are sent back to the aircraft. The pulse which is reflected from the surface of the water is a red beam (infrared) which measures the aircraft height above the water and is directed vertically downward. The beam which reflects off the seabed is a green colour and is examined over a semicircle of +/ -15 degrees to the planes bearing and pulsates at approx 160 pulses per second. The aircraft's equipment will record the speed of the wave and the travel time during air to calculate depth.
Personal Watercrafts or "jet skis" are basically Personal Watercraft (PWC) are basically small inboard boats able to travel at high speeds due to large amounts of power and very light weight. Alomst all PWC's are under 600 lbs and most of todays PWC's have at least 90 hp.Not only are PWC's some of the fastest water vehicles they are also some of the most maneuverable water vehicles. This is because PWC's propultion is based on a jet that also is it's turning mechanism. When the driver turns the handlebars the jet (via cables) turns in the direction of the handlebars so the stern is pushed in the opposite direction. This allows the driver to turn at a much tighter angle than traditional boats with keels and rudders.The main drawback to this maneuverability is the fact that if there is no thrust coming from the engine the ability to turn is effictively zero meaning that anytime the driver presses the kill switch (a large red button) they lose all ability to steer. This is extremely dangerous whenever an inexperienced person may drive the PWC back to dock or into shore. PWC's have no brakes and have no ablilty to stop other than turning around. They have an extremely efficient ability to hydroplane (when most of the PWC is above water) and it takes most PWC's a few hundred feet to come to a stop after being at full throttle. This is because 600 lbs + a rider is traveling at a very high speed with only minimal friction to slow them down (since PWC's are made to travel with very little friction).
Hurricanes form over the ocean. Easterly waves, what hurricanes develop from, are long, narrow regions of low pressure which occur in ocean winds called trade winds. At first, these easterly waves can grow into something called, a tropical depression. A tropical depression occurs when winds are up to 31 mph. Then tropical depressions can be upgraded into a tropical storm if the winds reach speeds of 74 mph or less. Then finally a the storm can be bumped up into a hurricane if the winds reach 75 mph.
The Sun’s radiation heats the upper atmosphere, sending the energy toward the earth’s surface and finally mixes with the planet’s counter-rotational currents, creating jetstream flows. The winds flow over the ocean’s surface creating friction that spawns chops, pushing up the seas forming perfect bands of open ocean swell. Pushed on by gravitational forces, the swells speed away from the winds that they came from, moving across the deeps until they feel the drag of the shallows near the coast. As the swells rise up out of themselves, they peak, curling into the liquid dreams that we surfers ride (Kampton 4).
In the article “A Tsunami, Where?” (2015). On June 2013 a storm have hit the East Coast in the U.S that results in tsunami. Over 30 tide gauges have reported similar tsunami conditions. The highest capacity was recorded in Newport located in Rhode Island. In addition, Conditions showed a conceivable torrent, even to the individuals who did not have the guide of the tide gages. Brian Coen was spearfishing at Barnegat Inlet in Ocean County, New Jersey he saw a solid outrush of water as the tide went out. Outrush conveyed jumpers over submerged rocks that serve as a barrier, the strong waves carried the three drivers but only two were harmed. However, Ebersole reviewed that before long, the current switched at the same pace. A close-by gage recorded
Rough waves are an open water phenomenon, in which winds, currents, nonlinear phenomena cause a wave to briefly form that is far larger than the "average" large occurring wave of that time and place. rogue waves can form in large bodies of freshwater as well as the ocean. The first rogue wave confirmed with scientific evidence,it has a maximum height of 25.6 metres (84 ft).rogue waves can also reach up to about 30 meters or 100 feet high. A rogue wave estimated at 18.3 meters (60 feet) in the Gulf Stream off of Charleston, S.C.
waves. The waves at the front of the boat are compressed and are shorter than the longer, spread out waves at the back of the boat.
Think about it for a moment, each time a surfer goes to a beach, waxes up his board, and surveys the waves from the shore, he is preparing to go into the water to do something quite amazing. This person is willing to test not only his limits, but also the limits of what the ocean can do to him. He wants to battle the power of the entity that covers over seventy percent of the earth, manifested in the form of a wave, and ride it for all its worth.
Computer games have steadily become a form of mainstream entertainment ever since Pong was released back in 1958. Today, it is hard to find an electronics department in any store that doesn't carry some sort of computer game. "Big deal," you say, "Everyone knows about computer games. What does they have to do with physics?" Well, the technology for creating more powerful software is constantly advancing, and since games are a form of software, they too become more and more advanced. As games become more advanced, game developers aim to create games that offer a more realistic experience. The technology has advanced to such a stage that making the games look real is no problem, but making a truly immersive experience is something different. That's where physics comes in.