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Welcome to Martin’s Head beach home on the shore of Fundy Bay where there are some of the largest tides in the world. The posted coordinates will bring you to the edge of the water at low tide.
All tides are primarily caused by the Moon, so they are on what one might call "Moon Time." The moon circles the Earth about every 24 hours and 55 minutes, meaning that it rises about an hour later each day. Generally there are two high and two low tides each day, for a total of four. The pull of gravity from the Moon and the Sun are the primary cause for tides. The effect is the greatest when the Moon and Sun are in a straight line with the Earth, which occurs during a Full Moon or New Moon and is called a spring tide. When this is coupled with the configuration of the shore and ocean floor the tidal range is greatly affected. Since the Bay of Fundy has a large mouth, with an ever-narrowing passageway to the head of the bay, the enormous volume of incoming tidal water is forced upward, causing the great tidal differences.
The Bay of Fundy is the northern terminus of the larger Gulf of Maine and separates southern New Brunswick from Nova Scotia. The Bay of Fundy is a 170-mile-long (270km), straight-sided, somewhat funnel-shaped bay, which splits at its northeastern head into two narrow bays, Chignecto Bay and the Minas Basin. It was formed as the continental plates parted millions of years ago. As they split, deep rift valleys formed, which quickly filled with sediment washed in from the land. The Bay of Fundy is one of these ancient rifts. It is one of the natural wonders of the world. The physical features of the bay are truly amazing. Twice a day 100 billion tons of water rush into and then out of the bay, which is more than the combined flow of all of the world’s freshwater rivers! The bay is wide and deep at the mouth, and shallow and narrow at the head. As this enormous volume of water moves up the bay, a funnel effect amplifies the tides, which range from 3.5 meters or 11 feet at the mouth to 16 meters or 53 feet in Minas Basin at the head. A contributing factor to the tidal amplitude is the length of the Bay. The time it takes a tidal wave to move from the mouth of the bay to the head and back is almost exactly the same as the lunar tidal cycle. This forms a resonant wave called a "seiche" that adds to the already massive tides. This means that the tides range is amplified, similar to the effect produced by children sloshing water into waves in a bathtub. These two factors, combined with several other lunar features, make the tides of the Bay of Fundy a natural wonder of the world.
Remember this is an earthcache so there is no container just an earth science lesson at an amazing natural feature. In your log please take the time to describe what you find special about this wilderness beach. The posted coordinates are the mouth of the brook at low tide. To log this earthcache you must answer the following question by getting as close to the coordinate as you can without getting your feet wet. Post in your log a description of the erosional effect at the time of day of your observation, include the coordinates and the distance to the cache when you log the find, as include the size of your group. You must also mention if your visit was closer to the neap tide or spring tide (see educational notes). It would be nice to post a photo so that others have something to look forward to during their visit.
You should be able to compare your tide time to the real tide time by looking at the local tide tables located in most stores and marinas in the area.
EDUCATIONAL INFORMATION: The Earth and Moon together--due to their gravitational attraction to each other--act as one unit. Think of this body as something like a sledge-hammer, where the head of the hammer (the largest and heaviest part) represents the Earth. The handle represents the distance between the Earth and the Moon, as well as the mass of the Moon, itself. If you try to balance the hammer on your finger, you'll see that the center of gravity isn't in the center of the hammer's head, but is somewhere between the center of the hammer's head and the bottom end of the handle. It's the same with the Earth-Moon "unit." So, the Earth actually rotates on an axis other than the actual North-Pole-to-South-Pole axis; it rotates on what is called the "Barycenter." The Barycenter is the center of gravity of the Earth-Moon unit. As the Moon revolves around the Earth, the Barycenter moves with it! Therefore, the axis on which the Earth rotates is constantly moving! And, since the Moon's orbit around the Earth is an oval, not a circle, the Barycenter moves in and out, along with the Moon's distance from the Earth. Note, though, that if we were to average the location of the Barycenter, the result is very close to the North-Pole-to-South-Pole axis. Because the Barycenter is around 1,000 miles below the Earth's surface, that means that the side of the Earth that's opposite the Moon is travelling faster than the side of the Earth that faces the Moon. Therefore, there's a great centrifugal force on the Earth's side opposite the Moon. Thus, the Earth's rotational axis (running from the true North Pole to the South Pole) is sometimes shown as one that wobbles a bit. This great centrifugal force throws the water outward, creating the high tide on the side of the Earth that's opposite the Moon. This far-side high tide, although high, is not as great as the high tide on the Moon's side of the Earth. Therefore, there is one "higher high tide" and one "lower high tide," as well as one "higher low tide" and "lower low tide" each day.
As such, you can reasonably expect to see at least one high and one low tide during daylight hours. Tide times move ahead approximately one hour each day, and tide times vary slightly for different locations around the Bay. Remember tides are created by the gravitational pull of the moon. As the moon revolves around the earth it causes large bodies of water to bulge or pull slightly in the moon's direction. This bulge, as it moves around the globe results in the rising and falling of the tides. The alignment of other terrestrial bodies such as the sun with the moon can affect the amplitude of the tides as well. Accordingly, during a full and new moon, the tides are the highest. And during solstice time period, there is an extra high tide. The powerful scouring action of the Bay of Fundy tides creates a striking coastline. The Spring Tides is when the moon is full or new, the gravitational pull of the moon and sun are combined. At these times, the high tides are very high and the low tides are very low. This is known as a spring high tide. Spring tides are especially strong tides (they do not have anything to do with the season Spring). They occur when the Earth, the Sun, and the Moon are in a line. The gravitational forces of the Moon and the Sun both contribute to the tides. Spring tides occur during the full moon and the new moon.
While the Neap Tides is during the moon's quarter phases the sun and moon work at right angles, causing the bulges to cancel each other. The result is a smaller difference between high and low tides and is known as a neap tide. Neap tides are especially weak tides. They occur when the gravitational forces of the Moon and the Sun are perpendicular to one another (with respect to the Earth). Neap tides occur during quarter moons. This should help you better understand the erosive effect of 100 billion tons of water moving in and out of the Bay twice every 25 hours. It has sculpted spectacular cliffs, sea stacks and caves.
Additional Hints
(Decrypt)
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