Water Features! 5th May ’09

This was Ms Tang’s second last lesson with us, and it was the one of the few times when I actually paid extra attention to the lesson, partly due to the fact that I had to do this blog post. However, I found this lesson rather interesting, when we learnt about waterfalls and rapids. This was what we learnt…

The formation of waterfalls: As water flows over the bedrock, the less resistant (‘soft’) rocks erode first. As the less resistant rocks keeps eroding, the gradient of the slope gets steeper, thus the formation of waterfalls. There is usually a plunge pool at the end of the waterfall, due to the force of the water hitting the bottom.

The retreat of waterfalls: Eventually, the more resistant (‘hard’) rocks will start to erode, thus the gradient gets less steep. However, the main cause of the retreat of waterfalls is the collapsing of the overhanging hard rock due to the erosion of the soft rock.







The formation of rapids is almost similar to that of a waterfall. The ground consists of alternate layers of ‘hard’ and ‘soft’ rocks, with the ‘soft’ rocks eroding first, thus forming a ‘step-like’ structure that resembles a mini waterfall.



Reflections:

Learning about the formation of these natural wonders is rather interesting. It seems so well planned yet it is a natural process, thus I enjoyed the lesson thoroughly (it’s my first time complimenting on Geography). Lesson was as usual, in a hot and stuffy classroom, everyone was noisy while the two groups were presenting on their respective topics. I finally realized that geography is actually a subject which ‘makes sense’. For instance, the steeper a slope of the waterfall, the faster/more the water flows, thus the formation of a waterfall…etc.

-Kevin (finally...)