What Causes High Tide And Low Tide ?
You probably be knowing that waves located on the ocean’s surface are commonly caused by wind transferring its energy to the water but do you know what causes ocean tides ? How come there’s rise and fall of sea level everyday ?
Well, there are various factors those are involved in tide’s creations but major factors are gravitational pulls of the earth, moon and sun. In fact the biggest factor in creation of ocean tides is the moon. It exerts approximately 2.2 times more gravitational force on oceans that sun does. Whenever there’s is a full moon, gravitation force exerted by moon on the ocean is at peak which causes longer high tides and vice versa when there’s no moon.
What causes high tide and low tide ?
As we know, earth and moon constantly exerts gravitational force on each other. Considering this fact in mind, imagine moon is directly above earth. Since 71% of earth is water which is in liquid state, it gets affected by gravitational force of moon. This causes to move water present in oceans to move towards the moon which creates high tide on earth side that is facing the moon as shown in following image.
At the same time one more interesting thing happens to opposite side of moon facing earth. Because of gravitational pull, earth also actually gets pulled little bit towards moon and being at opposite side, there is not much effect of moon’s gravitational force on ocean water on this side so water doesn’t move towards moon. That means, earth moves little bit towards moon but water doesn’t which creates high tide on opposite side as well.
In summary, because moon is pulling water present on moon facing earth side a high tide gets created and at the same time as moon is pulling earth but not water of oceans at opposite side of earth, a high tide gets created. As high tides got created at top and bottom, it’s obvious that there will be low tides on sides or right angles to the moon.
Sun also affects tides but not as much as moon. Depending on angle to the moon, sun may enhance or diminish the effect of moon on tides. If sun and moon are aligned to the earth, sun enhances the gravitational force on earth creating higher tides than normal. These are called spring tides and they happen on full moon or new moon. When sun and moon are right angle to each other, sun diminishes effect of moon’s gravitational pull on earth creating lower than normal high tides. These tides are known as neap tides. Usually in most of the places, high tide is observed twice a day. Approximately at every 12.25 hours.
Now you know what causes high tide and low tide If you are still confused in understanding how a high tide gets created on opposite side of moon facing earth side, watch the following video for animated representation and more detailed explanation.
Courtesy : The Cosmos Is Also Within Us