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Ocean Tides
Affected by the gravitational pull of the moon and sun, sea levels rise and fall on a daily basis. Ask questions here about high tide, low tide, spring tide and neap tide.
1,277 Questions
Why does Perth only have one high tide a day and Melbourne have two?
The interaction of the Sun and Moon's gravity with the oceans produce tides. If the Earth was a just a ball of water (no land masses) then there would be 2 tides per day everywhere.
However there are land masses that complicate the tide movements, so that there are 3 different types of tides, depending on the local geography.
1. Diurnal - one high tide and one low tide per day. Occurs in Alaska, South East Asia, Gulf of Mexico and Western Australia.
2. Semi-Diurnal - Two high and two low waters per tidal day. They are common on the Atlantic coasts of the United States, Europe and Africa.
3. Mixed Tides - as the name suggests, each tide is different from the last. Occurs everywhere else!
When boating on coastal waters it is important to be aware of the tide. Why?
Because tides can change the depth of the water by an important amount. Underwater obstacles you can pass at high tide might catch you at low tide. Or even leave you stranded.
Tides can also cause strong currents. Usually not a problem for motor boats, but they can bring sail boats/and really slow motorboats to a standstill.
What causes tides to be much higher at many seaports at sea?
Much higher than what?
The variation from high to low tide at any given point on the shore is a complicated function of the local topography and ocean currents. Narrow, shallow bays or inlets tend to "funnel" in seawater at high tide: the Bay of Fundy (in Canada) has the most extreme tides in the world, where there can be a difference of over 50 feet between high and low tide.
Large tidal ranges are actually a problem for seaports, because it's difficult to moor boats when there can be several meters difference between high and low tides. The busiest naval port in Europe is Rotterdam, where the tidal range is only around 2.4 meters, and the busiest port in the world (Ningbo-Zhoushan, in China) has a tidal range of well under 2 meters.
There are other considerations as well, of course (access to a deep river or canal system for further transport inland was historically important), so some busy ports do have larger tidal ranges (Singapore and Shanghai have ranges closer to 4 meters), but it's the exception rather than the rule.
When boating on coastal waters it is important to be aware of the tides. Why?
Tides cause water levels to rise and fall.
Who wrote The tide recedes but leaves behind?
Written by MD Hughes.
The Tide Recedes
The tide recedes, but leaves behind
Bright seashells on the sand.
The sun goes down, but gentle warmth
Still lingers on the land.
The music stops, and yet it lingers
On in sweet refrain.
For every joy that passes
Something beautiful remains.
How many times do tides occur on the Texas coast?
there are two tides a low tode and a low each happen once a day
Are the tides on earth caused by the gravity?
Tides on Earth are caused by the gravity of the moon and, to a lesser degree, the sun.
How long is it between high tide and low tide?
6 hours... at least that is what study island says. i hate that website.
The difference between water levels at low and high tide-?
Water level is how deep the water is. High and low tide is when the water is washed in and out.
Where are high tides located in relation to the Moon?
There are "sub-lunar" and "antipodal" high tides.
The sub-lunar tide occurs when a place is, roughly speaking, directly "below" the Moon in the sky.
It's when the place is as close as possible to the Moon on any particular day.
The antipodal tide is the one that occurs right on the other side of the Earth,
as far away from the Moon as possible.
That's the basics, but there are a lot of complications with the tides, of course.
Should you snorkel at high tide or low tide in key west?
It depends really on how confident you are as a swimmer. If you are capable of swimming in high tide then swim in high tide but if not swim at low tide.
i think you mean "neap" tide and it means a tide of small range occurring during the first - and - third quarter phases of the moon! ..... ha ha "heap" tide
What is the lowest tide called?
That would be the neap tide. It produces the lowest low tide, whereas the highest high tide is called a spring tide.
What criteria does whirlpool design team use in design decisions?
Whirlpools are natural phenomena caused by sea floor topography and the tides. They are not designed by a team.
When is the low tide of high tide is at noon?
There is no such thing as a low tide of high tide. Tide is either low or high but it can't be both at once. Tide times change daily depending on where exactly you happen to be. You're going to need a tide chart - you can find those online or pick up a free one at coastal stores.
What is it called when tides are especially strong due to the alignment of the sun and moon?
spring tide
Tidal forces depend on both the mass of the object and the distance from it. Tidal forces are directly proportional to mass and inversely proportional to the cube of the distance. This means that changes in distance have a greater effect than changes in mass. The sun is about 27 million times more massive than the moon is, but is also about 390 times farther away. If you do that math on this, it works out that the moon exerts roughly twice the tidal force on Earth that the sun does.
What tides occur during the full and new moons?
so called 'spring' tides. this spring has nothing to do with the season that comes after winter. these tides have an increased range with the tide coming in further and going out further compared to so called 'neap' tides.
