We started the lesson (21 April 2011) with a recap of what we have learnt the previous lesson,
which is, what is erosion (a process of wearing down), transportation and deposition (the dropping of sediments in order to regain back energy). Among all theses processes, erosion takes up the most energy. We then went on to answer the question Ms J asked us in the previous lesson, 'How do you think waterfalls, valleys, floodplains, deltas, distributaries and meanders are formed?' We started with waterfalls first. Ms J told us to try and see if we knew how they were formed. After a while, Chrystal, Nicole and I came up with an answer. We knew it has something got to do with erosion. Our explanation- it was a slope at first, then as the water flowed down, the water erodes the sides. To help you understand what we had in mind, check out a drawing I 'drew':
Blue-water, brown- original slope, purple to yellow- process, green- nowI thought it was quite an explanation. However, like always, geography isn't easy and clear-cut. It turns out that the correct explanation is:
Okay, so it's like this- believe it or not, it is actually a rock at first. Not just any rock, though. It has to be a rock with different layers, soft and hard. Yes, there is such a thing. Anyway, the water erodes the rock. Obviously the easiest to erode is on the soft rock layers. so it erodes and creates what you see in the diagram. There are some parts that are missing, though. Do you know where is the plunge pool, overhang and notch are? Yes, the plunge pool is the place where there is what looks like a swimming pool under, in the diagram, the place labeled soft rock layer. The overhang is the point which the watyer flows down, and the notch is the place where, in the diagram, seems 'untouched' by the falling water.Cool, right?
I found interesting websites while doing my research, and they are relevant to geography. Check them out!
All the best for the upcoming Common Tests!
Hi Chrystal and Joanne,
ReplyDeleteGood post! shows that you learn although you made some mistakes at first. I'm glad that you showed the pre and post diagram of your understanding of waterfalls. Just want to clarify one thing, soft and hard rock aren't just rocks of different layers, but to be more accurate, rocks of different RESISTANCE.
Since you've mastered this process of formation of waterfalls, go do some reading up, are there other ways in which a waterfall can form? Apart from erosional processes.
-Miss J