weathering erosion and deposition are three important vocabulary words so it's important that you understand the definition of each of these key terms weathering is the breaking down of rocks and minerals into smaller pieces and you can see that this layer of rock has been broken down into lots of different pieces and some of those pieces are very small but anytime we break down a rock into smaller pieces we call it weathering wind and flowing water can cause rocks to be weathered on the left you see how all those rocks are smooth that's because water has weathered those rocks it has broken off all the little bits around them until eventually the water has made them smooth and on the right you can see how those rocks are broken and cracked that's been caused by the weathering of the rocks from wind and water glaciers are huge masses of ice that can break apart and grind down rocks as they move across a landscape so just for scale there's some people right there in the picture and you can see how big that glacier is and glaciers move across land and when something that big moves across the land it's going to break down and weather the rocks in its path ice can also break apart rocks as it freezes and expands inside cracks so if it rains water can fill in the cracks in a rock and then maybe at night it gets cold enough for that water to freeze when water freezes it expands and so it can push on the sides of the rock and actually make those cracks a little bit bigger and then maybe in the daytime it gets warm enough for that ice to melt and thaw and that water can go down into the cracks and at night when it freezes again it can expand a little more and eventually that ice can break the rock apart and weather the rock causing it to break apart into smaller pieces now this doesn't happen in just a couple days it can take a long long time for ice to do this to a rock but it can happen and here are some examples of rocks that have been broken apart by ice now remember anytime rocks are broken apart into smaller pieces we call it weathering so this is how ice can weather a rock so our next term is erosion and erosion occurs when pieces of rock and soil called sediments are carried from one place to another and you can see that happening here in this river it is brown because it is so full of sediments and it's carrying them from upstream down the river from one place to another so this is a great example of erosion wind can easily blow sediments across a landscape and that's very common in the desert strong winds are very easily able to carry those grains of sand from one place to another in a desert so as we saw earlier with our river sediments can also be carried to new locations by the water from rivers streams and floods and you can see that water is causing the erosion of this soil it is carrying the soil away from here to another place the water is eroding the soil and our final term is deposition and deposition is the process of sediment soils and minerals being dropped or deposited in a new place so sediments are carried by something like the river and when they get to a new location where maybe the water slows down those sediments fall to the bottom they settle out of the water and are deposited in a new place grains of sand are blown across the desert by strong winds and they eventually land in a new location so they get deposited and build up over time into a dune and so sand dunes are caused as strong winds blow sand across the desert and that sand is deposited into these hills that we call dunes so as we've already seen sediments are carried by a river downstream but when the river enters a lake or ocean the water slows down as the water slows down the sediments settle out of the water so that fast moving water is easily able to carry those sediments and push them downstream but once it slows down all those sediments start to settle out to the bottom of the lake or the ocean and over time the layers build up as sediments are deposited so you can see here this deposition of sediments over time builds up layers and deltas are formed as sediments are deposited at the mouth of a river so as the river slows down it dumps all of those sediments kind of right as it goes into the ocean and over time that builds up until eventually you get this of soil that's been carried downstream and it's very rich in nutrients and it's very easy for plants to grow there and we call it a delta so i hope this video has helped you understand weathering erosion and deposition a little better keep up the great work and i'll see you next time