♥ Wednesday, January 28, 2009 ♥
Basically, we did the mindmap in groups and talked about carbon cycle today.
At first, we discussed and reorganised our mindmaps in groups. Forturnately, my group was chosen to present our mindmap to the class.Based on our own mindmaps, we have come up with a mindmap that combine the important points in our mindmaps, clearly presented by Alissa, evaluated by Li Qin, and was givin a quite high score.
Back to the topic, the question here is : How is atmosphere essential for life?
At first, when i do my mindmap, I just read through the notes given and copy all the useful points on a piece of full scap. But it looks like an essay, rather than a mindmap. However, after today's lesson, I realized that knowing the facts does not really answer and explain the question. What I should do is to think before I draw a mindmap. What do I know about the topic? Is it important enough to be in the mindmap? and so on and so forth.
Questions like this could help me organise ideas and give a clearer way of seeing the whole big picture.
Since, everyone must have known the concept and the mindmap very well, I would not go into that part further.
Something that is quite new to me is the carbon cycle part.So I'll try to describe it in my own words, hopefully, everyone could correct me if anything is wrong.
In the atmosphere, there is 0.03% of carbon dioxide, which is very little, comparing to other gases like nitrogen and oxgen. However, it is important since it's the basic material for plants to photosynthesize. Carbon dioxide is turned into sugar, mainly glucose and starch through the process of photosynthesis and stored in the plant. Animals will consume plant, use the sugar to provide energy to their body. After decomposition of animals' dead body, carbon will return to atmosphere. Besides, carbon also returns to atmosphere in the form of carbon dioixde as a product of animals' and plants' respiration.
If the dead plant or animal is not completely decomposed, they will turn into fossil fuels. In this way, carbon will be stored in the earth for quite a long time.
Carbon dioxide in the atmosphere also dissolves into the ocean, providing aquatic plants energy, and starts the carbon cycle in the ocean. A different way of carbon being stored in the ocean is that carbon is taken by oyster, forming the seashell. After the oyster died, the seashell will not decompose, in stead, it will become sediments and finally form the limestone--a kind of sedimentary rock.
It seems very easy to understand the carbon cycle with reference to the mindmap.And to understand everything in a system is easier than memorizing the facts.
Despite all of this, Mr Heah mentioned the regulatory force in the nature that keeps the carbon cycle balanced. Well, I have not figure out that yet. And still, I wonder if the earth was formed with the specific percentage （0.03%） of carbon dioxide in the atmosphere. If it's not, was there a regulatory force? And what's the use of regulatory force if there's no consumption of carbon ( when there's no animals, or plants)？
Hope my question is answered soon.
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♥ Wednesday, January 21, 2009 ♥
Today Mr Heah didn't come to class. So we watched a video about the Earth's Atmosphere. It was pretty interesting. It was about this traveller who went around the world.
Let's clear this up. I will refer to this traveller/host of the show as he throughout this post. Not in any order, I will try and describe the entire show to everyone.
He travelled to Siberia where he found trapped methane underneath the ice. He and another lady dug through the snow to the ice surface of a lake I think, and they found many air bubbles trapped in the ice. To test whether the gas in the bubbles were methane, they set fire and see if it would burn. It was quite a sight. Fire on ice. Methane is more potent than Carbon Dioxide. If the ice melts in Siberia and these large amounts of methane in the permafrost gets released into the atmosphere, it would be a disaster.
He also took a fighter jet and flew into the atmosphere. When we see shooting stars, it is actually a meteors burning up in the mesosphere. The mesosphere protects us from all meteors that comes crashing into Earth. The stratosphere is the layer where it absorbs most harmful rays from the sun protecting us. And there was this guy who took an air balloon up into the sky and went even higher than he did. And when that air balloon guy reached a certain level, he jumped out and experienced free fall for a few seconds.
Next there we saw this huge cloud and there was this man who sky dived during free falling. Pretty interesting. Shows us that we can "surf" in the sky as he called it. Instead of falling straight to the ground, he can maneuver the board that was attached to his feet to move horizontally.
Then there was a theory about how the earth atmosphere was formed. It started of with countless of eruptions from volcanoes spewing out carbon dioxide and methane. Then came an organism that started to photosynthesis giving our atmosphere oxygen. As the amount of oxygen increased, the more and more organisms come alive.
There were also many others about the sahara desert blowing sand which contains many minerals to the Amazon rainforest (I think). And there was a one on the lightning at a high mountain range, Andes. It was showing how lightning looks like at different layers of the atmosphere. There was another about the rust forming under the ocean as oxygen got produced and reacted with the iron under water. After many years, the ocean dried up and left behind rocks with bending where we can see the different layers. We also saw how our atmosphere got shaped over time by the wind and sand providing amazing natural landscapes (Arizona).
All in all, today's lesson was fun and enriching. The video was informative and showed us a lot of the world and the earth's atmosphere that we don't know.
A reminder to the class: Do up your mindmap before the next lesson because Mr. Heah will go through it then :)
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♥ Monday, January 19, 2009 ♥
Today Mr. Heah taught us the basic knowledge about the composition and structure of the atmosphere. At first, I wondered why we should learn such a common knowledge that everyone knows it in primary school. But later I noticed that it is not as simple as I think.
It is definitely true to say that the atmosphere is essential for life, but why it is? You may say that because it has oxygen and people need oxygen to stay alive, but why oxygen is, why could not be nitrogen since it constitutes 78 percent of the atmosphere? All of these I have never questioned myself before. That’s why when I started thinking them I found that Geography is more than memorizing. It can be linked to other scientific subjects and remembered by thinking logically.
The composition of air basically includes three parts: 78% of Nitrogen, 21% of Oxygen and 1% of other gases. The oxygen plays an important role to sustain our life because of its reactive property. It can form compounds with lots of elements and moderately soluble in water so that we can easily use it as respiration and other necessary biological activities. Other gases like nitrogen and helium, is either too stable or too reactive.
However, there is another gas in atmosphere that only constitutes 0.036%. It is carbon dioxide, the so-called waste product of all living creatures. Mr. Heah asked us what if there is less carbon dioxide in the air. As my opinion, I do not think it is good for us although it may help solve global warming or whatever. Carbon dioxide is as important as oxygen in the world. It is the key of the carbon cycle which helps balance the spheres and interacts properly between the layers. If there is less carbon dioxide in atmosphere, it will also be less carbon dioxide dissolves in the waters of the hydrosphere. Thus, the land plants and aquatic plants can hardly survive without enough carbon dioxide to photosynthesis and make food.
Otherwise, we also learnt the structure of the atmosphere. It has five spheres: troposphere, stratosphere, mesosphere, thermosphere and exosphere. There was one question that puzzled me a lot and I hope someone can provide an answer. Actually Mr. Heah mentioned that it is something about the difference between temperature and heat.
The question is “why the temperature at the thermosphere is higher than 1200 degrees Celsius, yet you would freeze to death up there?”
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