how do the pebbles look in the middle and stuff thanks xx
2006-09-06 04:01:43 · 10 answers · asked by wa wa 1 in Science & Mathematics ➔ Geography
The water flows downstream, and take the pebbles with them. At the beginning they are sharp and big, but as they are taken downstream by the water, the water rushes past them and erodes the edges making them smoother, smaller and more blunt!
2006-09-06 04:06:47 · answer #1 · answered by Little Miss Helellena 3 · 0⤊ 0⤋
This is Geology/Physical Geography, love it. It's all to do with the size and weight of the pebbles/rocks and the strength of the water current in the river or stream.
Upstream the river current will be strong, so the only rocks/pebbles which will be deposited are the very large ones which are too heavy for the water flow to carry. Progressively as you move down the river the water flow/current weakens, so progressively the pebbles that can not be moved become smaller and smaller. Eventually as the river widens into an estuary the current and flow of water drops right off, so the last deposits to be dropped are sands, muds and silts, hence the formation muddy estuaries bars and creeks. What the pebbles look like in the middle depends on what rocks they were formed from. There are many different types of rocks, igneous, metamorphic and sedimentary, plus a whole host in between. If your really interested then go to http://www.geog.le.ac.uk/cti/geol.html
What I like about geology and physical geography is that it is all around you to see.
2006-09-06 11:18:29 · answer #2 · answered by Chariotmender 7 · 1⤊ 0⤋
Hi. Passing through a stream or river just once is not enough to make a smooth pebble. Most are made by the action of waves or ice (glaciers) over many years. The rocks upstream are bigger only because the smaller ones have been washed downstream.
2006-09-06 11:09:39 · answer #3 · answered by Cirric 7 · 0⤊ 0⤋
Plenty good answers how the further the stone travels the more it wears. The question how does it look in the middle if you mean the middle of the stream, well it won't be as worn as the bottom of the stream but more worn that the top of the stream, but if you mean in the middle of the pebble find one not to big get a good hammer and try and break it open but remember to wear protective covering over your eyes as it's not a clever idea, if you are really keen you can get a stone saw / cutter which is a motorised wheel using water to keep the dust down and makes it safe to use .Wont to know more get a proper book before you start, it can be an interesting hobby cutting and polishing stones you collected yourself from streams ect. Wine fly
2006-09-06 12:01:58 · answer #4 · answered by alex winefly 4 · 0⤊ 0⤋
As water slows down it can carry less weight in stones, so the pebbles fall out according to size, largest first. Water slows down at a delta, on a curve, or just when the grade is less steep. As pebbles are rolled along the bottom they become rounder.
2006-09-06 17:45:46 · answer #5 · answered by science teacher 7 · 0⤊ 0⤋
rocks become pebbles after a long time, so pebbles are rocks that are upstream, the rocks are eroded due to weather, nature, temperature, streams and such, over time they hit against somethin, something hit against them and they might be too hot or too cold or burrowed into by small animals and get filled with water and such. due to all this, nature just take affect but it is a veeeeeeeeeeeerrrrrrrrrrrrrrrrrrrrrry long process.try reading soil formation in a geography textbook, you will find it exciting
2006-09-06 11:14:50 · answer #6 · answered by Yeahbabe 3 · 0⤊ 0⤋
In the upper course of the river rocks are large and jagged. As rocks and sediment travel through the middle course they become eroded, mainly by attrition (rocks hitting against each other and the river bed and sides). This means that by the time rocks reach the lower course they are smaller, smoother and rounder.
2006-09-07 05:12:33 · answer #7 · answered by Anonymous · 0⤊ 0⤋
Thusly!? Where did that come from - upstream with the boulders or on the beach with the little pebbles?
2006-09-06 13:55:01 · answer #8 · answered by cymry3jones 7 · 0⤊ 0⤋
the pebble size gets reduced due to erosion huge solid rocks are torn down due to thin shift rapids fron snow covered peaks . these r called boulders in the middle of course it is reduced to pebbles.at deltas this is called sand particles
the more u go up stream the bigger is the size of rocks
2006-09-06 12:11:36 · answer #9 · answered by Anonymous · 0⤊ 0⤋
The rocks will get get washed and bashed on the way down, thusly they will get broken up and worn down to smaler and smother sizes until you get sand
2006-09-06 11:04:21 · answer #10 · answered by poli_b2001 5 · 0⤊ 0⤋