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Homework Help: Marine Biology- Waves and Their Characteristics

  1. Apr 20, 2006 #1
    4. In strong storms at sea, ships often alter their course for safety reasons. They will travel directly into the direction from which the waves and wind are coming (even if this is not the direction they intended to go in). Why do you think it would be safer to travel into the wind and seas rather than at an angle across them?

    5. In extreme storms (this is different than question 4), ships may turn and travel in the same direction as the wind and waves are traveling (even if this takes them in the opposite direction they had planned to go). Why do you think this may be safer than traveling into the wind and waves?

    I've thought and thought and yet I can't figure it out...I'm sure it's a really simple concept but my mind doesn't seem to be grasping it. The experiment we were to do gave me conflicting information...

    10. In what direction does the WATER move in a wave? (trick question?) You might need to test this in your bathtub. Fill your tub with approximately two inches of water. Place a small floating object at one end of the tub and then place the bottom of a pan at the other end. GENTLY move the pan up and down to create small waves. Watch for the progress the object makes across the tub. Describe what you see.

    The first time I tried the experiment, the object floated towards the pan. The second and third times, I couldn’t get it to move much either way. The fourth time, I tried putting the object closer to the pan and the result was the object moving away from the pan and then stopping once it got out of the wave’s range. It appears that the water itself is moving away from the pan but I vaguely remember reading something about waves pulling you out to sea instead of pushing you onto shore.
  2. jcsd
  3. Apr 20, 2006 #2
    4 + 5) Try thinking about what effect the wind will have on the larger surface area (of the side of the boat) compared to the smaller surface area (at the front of the boat).

    What is going to happen to the ship if the wind comes from the front, and what about from the side?
  4. Apr 20, 2006 #3


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    4 and 5 seem pretty well covered by gen0688, just think about the forces involved and how you would best reduce those forces that are acting against the ship.

    Number 10- I'm going to assume that the question is loooking for water movement in a wave in the open ocean (aka- deep water). Water dynamics changes with decreasing depth of the water so be aware (more on this below). Anyway it's best to think of a particle in the wave and "see" how it is moving. You can do a google search for "particle movement in water waves" and you'll find your answer pretty quickly. As far as your experiment in the bathtub goes. You have to be careful not to generate waves with a long wavelength since a wave is affected by the underlying substrate, ie., the shore or your tub, at about 1/2 the wavelength. So if you are making large waves that particular 2 inch depth of water may not be deep enough to show you what the particle should do in open water. You will find that as you approach the shore the particle and the water moves in a roughly similiar fashion just a different "shape".
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