usually the water in a river flows towards the sea.But twice a day it flows in the opposite direction.-Why?

Question

What is this phenominon called ?

Answer 1

gravitational pull of the moon, tides

Answer 2

Gravity from astronomical bodies--but be careful, geography of the shore plays a role.

Read this and weep on Euboea, and the tides that carry back and forth up to 7 times A DAY (and it's pretty dramatic too, I've seen it).

Vote for me as best answer if this was helpful--geography, not just gravitational forces.

The extraordinary changes of tide which take place in this passage have been a subject of wonder from classical times. At one moment the current runs like a river in one direction, and shortly afterwards with equal velocity in the other. Strabo speaks of it as varying seven times in the day, but it is more accurate to say, with Livy, that it is irregular

Answer 3

The tide changes, high tide the sea water can go up the river. the river water is still going down the river unless it's a puny river.

Answer 4

Because of the gravitational pull of the moon over earths water reserves i.e. the oceans. The phenomenon is called tidal flow.

Answer 5

This is an indication of good fortune to come. Agitated waters mean you are likewise. Calm waters mirror your own state of the spirit. You have bounty coming from many places. Regards

Answer 6

because twice a day i send it in my canal to recharge the underground reserve of water.
There is no worse way to spoil the water that to let it go to the sea
It is better to lost it infiltrate the dry lands or évaporate it in the sun.
That why i do it
http://video.google.fr/videoplay?docid=-6428334944196136906&hl=fr

Answer 7

Tidal forces

Answer 8

Tide.

Answer 9

high tide?
low tide?

Answer 10

it s because of moon