Simulation Tides

Full Version 1.0 - © 2002 Steffen Maus und Daniel Roth - All Rights reserved!

Description  

The moon is moving around the earth. The gravitational effect on the earth's oceans (tides) can be observed. For better observation the relation between the displayed size of the earth and the tidal height is not similar to reality but 1:40.000 (no zoom selected) or 1:200.000 (zoom selected). In addition relative to the distance between the earth and the moon, their size is five times larger than in reality.

The background of the animation is a linear approximation of the theory. Effects of streaming water are not included in the calculation of the tidal heights. On the right side of the animation the tidal height is displayed in numbers and graphically.

    Zenit = the tidal height on the side of earth directed to moon
    Nadir = tidal height on the opposing side

Features

  • The appearence of the moon and the earth can be changed by editing the ".gif" bitmap files in the directory.
  • This Applet is "scriptable". This means that it can be configured and controled and that physical parameters of the simulation can be accessed by using JavaScript methods inside the embedding web page. More information about scripting can be found in the file scripting.html.

    The following methods are available:
    • jsStart()
      starts simulation

      jsStop()
      stops simulation

      jsReset()
      resets simulation

      jsSetDistance(value)
      sets the semi-major-axis to "value" (km). Valis values are between 10.000 and 380.000km.

      jsSetEccentricity(value)
      Sets the excentricity to "value". Valid values are between 0 and 1.

      ZoomIn()
      Zooms view by factor 5. The sizes of earth and moon are not affected by zooming.

      ZoomOut()
      Turns the zoom off.

      jsSetVisible(state,element)
      make user interface elements visible or invisible:

        state = "yes": make user interface element visible
        state = "no": make user interface element invisible

        element = "Start": button for starting/stopping simulation
        element = "Reset": button for reseting simulation
        element = "Zoom": button to control zooming
        element = "Distance": scrollbar and display of the semi-major axis
        element = "Eccentricity": scrollbar  and display of the excentricity
         element = "Diagram": diagram of the tidal height for zenit and nadir