Why are there two tides a day when the earth rotates once a day.?

Question

The moon attracts the earths seas so the tide should come in once a day not twice?

Answer 1

The tide is the cyclic rising and falling of Earth's ocean surface caused by the tidal forces of the Moon and the Sun acting on the Earth. Tides cause changes in the depth of the sea, and also produce oscillating currents known as tidal streams, making prediction of tides important for coastal navigation (see Tides and navigation, below). The strip of seashore that is submerged at high tide and exposed at low tide, the intertidal zone, is an important ecological product of ocean tides.

The changing tide produced at a given location on the Earth is the result of the changing positions of the Moon and Sun relative to the Earth coupled with the effects of the rotation of the Earth and the local bathymetry (the underwater equivalent to topography). Though the gravitational force exerted by the Sun on the Earth is almost 200 times stronger than that exerted by the Moon, the tidal force produced by the Moon is about twice as strong as that produced by the Sun. The reason for this is that the tidal force is related not to the strength of a gravitational field, but to its gradient. The field gradient decreases with distance from the source more rapidly than does the field strength; as the Sun is about 400 times further from the Earth than is the Moon, the gradient of the Sun's field, and thus the tidal force produced by the Sun, is weaker.

Answer 2

The moon is the primary cause of tides. It pulls the water closest to it upward. It also pulls the earth away from the water on the other side! So the water bulges on both sides of the planet, and is lower than normal in between those points. If you drew the earth and moon with the moon directly above the earth, you'd have high tides on the top and the bottom of your earth, and low tides to the sides.

Answer 3

The earth rotates only once. during the rotation when the moon comes near the the earth, it pulls water from the seas and oceans, so a high tide. The rest, - low tide.

Answer 4

For every action there is a reaction. If the tide is high on the side of the earth that is closest to the moon, and the sides of the the earth are flattened out, then the side of the earth that is on the opposite side to the moon has the lowest gravitational attraction, and thus can expand to counterbalance the closer side.

Answer 5

Tides are more reliant on the movement of the moon than the rotation of the earth. One tide occurs when the moon is closest (and the gravitational pull on the earth is the greatest), the moons gravity effects the movement in large bodies of water.

The other tide occurs when the moon is at its furthest distance from the earth (and the gravitational pull on the earth is the least), the lack of lunar gravity effects the movement in large bodies of water.

hope this answers your question.

Answer 6

(New Moon high tide spring tide)( Full moon high tide spring tide)
(1st quarter neap low tide)(3rd quarter neap low tide)

From high tide to high tide is 12 hours 25 minutes
To explain this it takes the moon 12 h 25 m to get from the north pole to the south pole
there are two tides every 25hrs
May 2005 from new moon to new moon 29 days

The earth rotates around the sun once a day
the moon rotates around the earth once every 25hrs

here are some links to put it into perspective
This first link explains the two high tides and two low tides
cool graphics
these links have links in them
http://home.hiwaay.net/~krcool/Astro/moon/moontides

This next one shows moon phases and calendar
http://en.wikipedia.org/wiki/Lunar_phase

Tidal range
http://en.wikipedia.org/wiki/Tidal_range

Spring tides are when the sun moon and earth are in a line
or when the sun earth and moon are in line
this link shows this
http://www.enchantedlearning.com/subjects/astronomy/moon/Tides.shtml

As you see more to the question as you go on so I will stop here

Answer 7

Because the earth is rotating and dragging the waters of the oceans along with it, the seas bulge out in two directions - towards the moon, and the other on the opposite side of the Earth, away from it, thus naturally balancing out.

Answer 8

Because the moon attracts the seas yes, but
that compresses the sides forming a crest 180
degrees opposite the attraction so that makes two tides every 24 hours.

Answer 9

Not quite 100% true

In Southampton they have 4 tides a day due to the additional local geography in addition to the sun and the moon.

Answer 10

The earth rotates all day long not just once a day. Plus, the moon is on a piece of string.