Friday, November 14, 2014

Tides Resource

Unfortunately, many people believe that tides are caused solely by the moon. However, the moon, the sun, and the Earth's rotation are all contributing factors to the pull of tides. The Earth rotates between a time span of 24 hours. Within this time, there are 2 high tides and 2 low tides. This means that every 6 hours the tide will shift from high to low or vise-versa. Noticeably, the moon is closer to different sides of the earth at different times, this is due to rotation. The side closest to the moon experiences the greatest force while the side farthest from the moon experiences less force. This video explains this by using a metaphor of a hose and objects. The object closest to the spraying hose experiences greater water pressure. We know this because of the formula: F=Gm1m2/d^2. Force is both affected by distance and mass. The radius of the earth greatly alters the distance. We also know that force is directly proportional to mass and inversly proportional to distance. In this way the side farthest from the moon experiences the smallest force. This difference in force creates a tidal bulge.  This happens because compared to the middle, there is a net force in opposite directions, on either side of the earth. During a spring tide, the sun, the moon, and the earth aline. This creates higher high tides and lower low tides. When they aren't in a line, it is a neap tide (normally the shape of an L). This video does a great job of further explaining this concept.

In this graph, we can see that Nags Head is currently in between high and low tide. Because it is a full moon, we are in a spring tide.



1 comment:

  1. Katie, I loved your explanation. The video you chose was a great reference and had many examples that were easy to understand and better explained tides. You then further explained tides as how they are affected by the moon using the Universal Gravitation Equation. By referring back to the video and using the tide chart to explain what moon phases have to do with all this, I can truly say that you have done a fantastic job. Props.

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