Why are there are no tides in rivers, lakes and other water bodies except oceans? The gravitational pull of the moon acts even on these water bodies!
Ram Kumar, Tenkasi, India
See Also
Why does a full moon mean a higher tide?High tides antipodes are caused due to.Centrifugal, centripetal and gravitational pull of the sunGravitational pull of the sunCentrifugal, centripetal and gravitational pull of the sun and the moonGravitational pull of the moon and the sunThe Caribbean: The Secret in the Sand42 USC 18302: Definitions- There are. But most bodies of water are too small for the effect to be great. On the other hand, check out the Great Lakes' tide tables.
Peter Brooke, Kinmuck, Scotland
- Firstly, tides are not simply caused by the gravitational pull of the moon as such. The moon doesn't revolve around the Earth precisely. They both revolve around their mutual centre of gravity, but because the Earth is so much heavier this means that the moon travels in large circles while the Earth travels in very small circles. It is this movement which causes the Earth's oceans, which are all interconnected, to "slosh" around, hence tides. Lakes would be very slightly affected but they are extremely small in comparison with the world's oceans, and not interconnected so they can't slosh around so noticeably.
Theoretically lakes must experience tides but the tides would be so small that even in the largest lakes the effect is masked by river inflows and wind and so on, all of which cause greater differences in water height than tides presumably must, so the latter are unmeasurable.
See AlsoWhy are tides lower in winter?Michael Fisher, Brisbane, Australia
- The sloshing around is also caused by the bulge of water attracted by the pull of the sun and moon. As the earth rotates daily, the coast is dragged through the bulge, and so the water level rises and falls each day. It is always high tide somewhere.The bulge in a lake is tiny, and enclosed, compared to the bulge in an ocean, because lakes are tiny (usually) compared to oceans, so there is no noticeable rise and fall. This is the reason the Mediterranean has less noticeable tides: it is a small ocean, and more enclosed, than others.
Tony Clarke, Glasgow, UK
- Indeed, tides exist in all bodies of water, even one's bathtub, but is so infinitesmally small, as to be unmeasurable. Even on Lake Superior, the largest of the Great Lakes of North America, the tiny effect of a tide is overcome by the effect of barometric pressure and the phenomenon known as a seiche. There are no Tide Tables of the Great Lakes and seiche warnings are rarely broadcast, as most cause a variance of less than 50 cm. The effects of a seiche may be felt strongest in the Straits of Mackinac between Lakes Huron and Michigan.
R. Manning, Marquette, Michigan, USA
- As Newton states in his expression for acceleration due to gravity that,- the force of Gravitational attraction is directly proportional to the product of the masses of two interacting bodies and inversely proportional to the square of the distance between them (ruling out the gravity constant) F=G x m1. m2 / r(squared)considering that they are at an equal distance from the moon ( thus ruling out r-squared), the mass of the Ocean is massive compared that to a lake or a bathtub or a bucket of water. Since it's mass being less, there is lesser gravitational attraction. So,it's 'size' that matters..
Akash Shesh, Mumbai India
