How on earth can moon create high and low tides?
147245
Actually only about 2/3 of the tides are from the moon's gravity, and about 1/3 are from the sun's gravity. \n\nThe reason there are about 2 high tides per day, is that the gravity field produced by the sun and the moon is not constant. The farther away from the moon you are, the less the gravity is. So water close to the moon gets pulled away from the earth (the force on the earth is less since the earth is farther away) and it gets pulled up in a pile we call a high tide. On the other side of the earth, the earth is pulled away from the water (since the earth is closer to the moon than the water on that side of the earth), leaving a pile of water on the far side of the earth, which is the other high tide. \n\nIn between these two piles of water, there are places where the water is not getting piled up. We say those places are experiencing a low tide. \n\nIt gets much more complicated than this of course. There are tides in the ground and in the atmosphere, in lakes and in rivers etc. There are places where there is one high tide a day or 3 or more or even no high tides per day (because of the response of the local area to the tidal forcing; governed by the bottom topography, coastline shape, etc). \n\nThere are high tides that are extra high because the sun and the moon line up (spring tides) and high tides that are not so high because the sun and the moon are at right angles, not working together (neap tides). There are ultra high tides when the moon is especially close (proxigean spring tides). There are effects of the other planets like Jupiter   and Mars in the tides. And so on.
64599
The maximum water level is called "high tide" or "high water" and the minimum level is "low tide" or "low water". High water occurs as two bulges in the height of the oceans; one bulge faces the moon and the other, on the opposite side of the earth, faces away from the moon. For an explanation see below under Tidal physics. There are two low waters positioned at about 90° of longitude from the high waters. At any given point on the ocean, there are normally two high tides and two low tides each day. The common names of the two high tides are the "high high" tide and the "low high" tide; the two low tides are called the "high low" tide and the "low low" tide. On average, high tides occur 12 hours 24 minutes apart. The 12 hours is due to the Earth's rotation, and the 24 minutes to the Moon's orbit. The 12 hours is half of a solar day and the 24 minutes is half of a lunar extension, which is 1/ (29-day lunar cycle). The lunar cycle is what is tracked by tide clocks.\n\nThe time between high tide and low tide, when the water level is falling, is called the "ebb". The time between low tide and high tide, when the tide is rising, is called "flow" or "flood". At the times of high tide and low tide, the tide is said to be "turning".\n\n \nThe height of the high and low tides (relative to mean sea level) also varies. Around new and full Moon when the Sun, Moon and Earth form a line, the tidal forces due to the Sun reinforce those of the Moon, due to the syzygy found at those times.\n\nThe tides' range is then at its maximum: this is called the "spring tide", or just "springs" and is derived not from the season of spring but rather from the German verb springen, meaning "to leap up". When the Moon is at first quarter or third quarter, the sun and moon are at 90° to each other and the forces due to the Sun partially cancel out those of the Moon. At these points in the Lunar cycle, the tide's range is at its minimum: this is called the "neap tide", or "neaps".\n\nSpring tides result in high waters that are higher than average, low waters that are lower than average, slack water time that is shorter than average and stronger tidal currents than average. Neaps result in less extreme tidal conditions. Normally there is a seven day interval between springs and neaps.\n\nThe relative distance of the Moon from the Earth also affects tide heights: When the Moon is at perigee the range increases, and when it is at apogee the range is reduced. Every 7½ lunations, perigee and (alternately) either a new or full Moon coincide; at these times the range of tide heights is greatest of all, and if a storm happens to be moving onshore at this time, the consequences (in the form of property damage, etc.) can be especially severe (surfers are aware of this, and will often intentionally go out to sea during these times, as the waves are more spectacular than ever). The effect is enhanced even further if the line-up of the Sun, Earth and Moon is so exact that a solar or lunar eclipse occurs concomitant with perigee.
1150942
Mean sea level is a average of all stages of a tide at a particular location.  There are many stages of tide; mean higher high, mean high springs, mean high water, mean high water neaps, mean lower low water, mean low water.  Mean lower water is the datum for nautical charts.  Local tides vary due to local geographic formations and lunar effects.  \n\nThe moon does not affect the water level of lakes since the amount of water is fixed.  Large lakes usually have high volume free flowing sources of water that may add or substract a noticeable quantity which may influenced by the moon.
540657
The desity of water makes it more suseptable to the pull of the moon's gravitation. Depening on it's course around the earth throughout the year the tides follow in it's wake. Not just hight tide and low tide are effected byt this but swells and tsunamis. The tides are also effected by plate techtonics but science has yet to decide whether the causation is more that plate tectonics are effected by the same gravitational pull as the ocean tides or my subterrainian thermo tides.
108928
The concepts of ebb and flow has a lot of contexts. Strictly speaking, the incoming tide is called a flow and the outgoing is called the ebb.\n\nTides on earth are caused by gravitional attraction with primarily the moon and to a lesser degree the sun. Water attracted to the moon is raised above the mean tidal level much like a bulge and the earth spins underneath this bulge. High tide corresponds to the highest point of the this tidal bulge and low tide is roughly 12 hours opposite.
588895
The obvious answer is the tides would be much smaller. We would still have tides, but they would be: (1) Caused by the Sun and therefore smaller. (2) They would come at roughly the same time each day.\n\nThis would affect a good deal of the marine life that depends on the tidal changes.\n\nLighting would also change. Reproductive behaviors in a number of animals are goverened by the moon's cycle. It is not known how much the moon's absence would change this.\n\nThe days would not grow longer as someone suggested. The opposite is true as the friction overcome in producing the tides takes energy. That energy is coming out of the earth's rotation and the moon's orbiting around the earth. The moon is slowly moving farther away and the earth is slowing down so the days are getting longer. Of course, this is an extremely slow process and you are not going to notice any change. The moon's absence would mean it wouldn't take place.\n\nEarthquakes would not be affected. They are caused by plate tectonics, which is independent of the moon.\n\nIf you are interested in the moon, try\nhttp://groups.yahoo.com/group/lunar-observing/\n\nHope this helps\n\nChuck
839020
The source of this energy is the spinning motion of the earth (not gravitational or orbital kinetic energy, although of course gravity is the agent by which the process occurs).\n\nThe two tidal bulges on opposite sides of the earth act like two jaws of a wrench lightly gripping a rotating shaft and causing it to slow down with the energy being converted to heat and radiation. This is causing the day to gradually lengthen and if the only source of the tidal force were the moon, the end result would be that the length of the day would eventually slow down to match the length of the month (that is, the same side of the earth would always face the moon) and at that point there would be no more tides or tidal friction. \n\nPart of the lost rotational energy of the earth goes into slightly accelerating the moon and pushing it gradually into a higher orbit. This is easily understood if you think of the wrench analogy. (In other words if the wrench gripping the shaft is allowed to move, part of the rotational energy will be transferred to the wrench (i.e. the moon) instead of being dissipated entirely as heat).
782867
no.  it affects the tides in a big way though, which can lead to weather.  But the moon doesn't affect our weather directly
387371
Sometimes a High Tide will occur and last long enough to cause the next Low Tide to occur on the next calander day.\n\nFor example: 1 Jan., Hide Tide: 6:01pm\n             2 Jan., Low Tide: 12:01am\n\nAlthough both happened within a 24 hour period (1 day). It will look a if there was a day without a Low Tide because they happened on 2 seperate calander days.\n\nBut, the moon could care less about our calander. It functions on 24 hour periods of its own. Within a 24 hour period you will have at least 1 high and 1 low tide.\n\nIf I've confused you, I'm Sorry. It made sense to me as I typed it.
467653
neap tide is the answer.\n\nExplaination. Since it is the effect of the moon and sun's gavity that causes tides, there are high tides closest and farthest away from the two of them. When they are lined up, spring tide occurs, resulting in the highest and lowest possible tides. However, when the sun, moon, and earth are at a 90 degree angle, the difference between high tide and low tide is the least(Because the effects of gravity are spread out). This is neap tide.\n\nPS. At neap tide there is still a visible distinction between the high and low tides. This is because the sun and moon's gravity and distance from Earth are not the same.
292483
It depends on how this change came about. If moon added mass (to a value > earth mass) then force between earth-moon also increases. So we have much larger tides, probably indundating much of the land. But we both keep coorbiting the sun. \nIf the change was caused by moon being closer to sun, then we're pretty much uninfluenced by moon, and tides are solar-only, having a large effect on shore life but not so disastrous to land-dwellers. \nIf the force just increased without any reason but still followed the inverse-square law, the moon, with its current solar-orbit velocity, moves too slowly to maintain the same orbit. Instead it would be at an aphelion (maximum distance point) of an elliptical solar orbit and would follow its new orbit. Since your condition says earth is further away from the sun it would not collide with us.
289483
tides are a result of the gravitational pull from the moon
43764
Tides happen in the atmosphere, and even in the ground itself. We can easily measure them with instruments. The solid earth tide is actually quite substantial, but it is still small enough and slow enough that we do not notice it usually. \n\nThere are definitely tides in lakes and in rivers too. Why would there not be ? \n\nIt should be noted that the tides are NOT because the water is attracted to the sun and moon. Tides are because the gravity field from extraterrestrial bodies (including other planets, not just the sun and the moon) is not constant. On one side of the earth, the force on the water is greater than it is on the earth, so the water gets pulled away from the earth. On the other side of the earth, the force on the water is less than it is on the earth, so the water gets left behind in a pile as the earth gets pulled away from the water. \n\nThis is why there are usually 2 tides per day, although it should also be noted that due to resonance effects, there are places with no tides, places with 1 tide per day, and places with more than 2 tides per day.
75841
The tides depend on not only the forcing of the sun, moon and other celestial bodies, but they depend on the shape of the bottom topography, shape of the coastline, etc. \n\nThat is why in some places there are two high tides a day (so-called semidiurnal tides, like in most of the world), some places there is only one high tide a day (so-called diurnal tides, like in California), and even some places with no tides at all, or 3 or more high tides per day. \n\nThere are also tides in rivers and lakes, but of course you can only see them if these bodies of water are big enough. There is also a good sized tide in the solid earth, and in the atmosphere too, as you might expect.
150643
The forces that the moon produces on the earth are very small. There is a periodic signal in barometric pressure corresponding to the atmospheric tide. However, my understanding is that there is no strong statistical evidence that tidal forcing has any effect on weather. It is possible that there is some subtle effect that might be uncovered, but it will not be easy. Even the effects of variations in the solar constant are not clearly seen in climate data.\n\n-----------\n\nAddendum: one does not need fancy equipment or satellites to measure the solid earth tide. It is a couple of feet, and it can be observed easy with accelerometers, and has been seen for decades.
578217
there is no place on this planet, or any other, that is not subject to tidal forces; whereever bodies are in orbit then gravity will produce tides.\n\nTides affect the land as well as any body of water, the effect may not be as obvious, but it is there.
1073218
1) Even without the moon we would still get tides. The tides are caused by both the sun and the moon equally. Solar tides would only be half as high as normal tides, and they would occur with a regular 12 hour rhythm rather than the monthly rhythm we get now.\n\n2) Tidal pools were NOT the places where land based species first got a foothold. The vast majority of land based species moved form fresh water onto land. This is the reason why earthworms, frogs, snails, mosses, ferns and so forth remain extremely salt intolerant to this day. It is actually very hard for a species to migrate from salt water onto land because it has to cope with the osmotic problems of rain in addition to the stress of dehydration. In comparison moving from freshwater to land requires only improved water retention.\n\n3) It would have been almost impossible for complex life to evolve without the moon. The moon locks the Earth into a stable position WRT the sun. As a result the equator always faces a the sun and the poles have always been perpendicular. Planets that lack large moons wobble, and at times the poles face the sun and the equator rotates perpendicular to the sun. At those times the temperature and light extremes would exterminate all complex life forms. Life would still be possible but every time the axis moved too far from perpendicular it would have to start afresh from deep sea bacteria.