Welcome back to week 2. Lets' go through today's main ideas:
Science
We went through a huge chunk of Man's impact on the environment, completing 2 experiments. Officially, we are done for the experiments for the syllabus for the year. Hooray!
1. Negative impact on the environment: Acid Rain
Acid rain occurs when chemicals and toxic gases dissolved in the rain before it hits the ground. Acid rain is harmful as it corrodes and damages buildings, statues, soil and living things. It is definitely harmful. It occurs when humans releases waste and harmful gases into the air through factories and burning which these gases then react with the rain to form acid rain. We carried out the experiment of putting a quail egg in vinegar and watching the acidic vinegar corroding away the shell of the quail egg. This shows the effects of acid rain (using the vinegar as an example).
2. Negative impact on the environment: Soil erosion
Soil erosion occurs when large chunks of soil is washed away by water. Soil erosion becomes harmful because it removes the top layer of soil that contains nutrients. As a result, habitats of animals and the animals themselves are affected and they may die. Also, if the soil washes into water bodies, the water bodies will be polluted, blocking out sunlight from entering the water and preventing water plants from photsynthesizing. Without the water plants, water organisms may die.
Trees are important as they hold the soil in place and prevent soil from eroding away. We carried out an experiment to test this concept today which held true.
3. Forests are important to the Earth and our survival.
There are plenty of reasons that tell us why forests are important.
- Cools the environment. (desert vs rainforest)
- Provides oxygen for us to breathe while taking in carbon dioxide.
- Provide wood to make products such as furniture and paper
- Provide habitats (homes) and shelter for animals
- Provide medicine (herbs)
- Prevent soil erosion
4. Greenhouse gases and Greenhouse effect
A greenhouse is a glass house made of glass walls and a glass roof. In it are plants. The sun passes through and heat is trapped inside, keeping the inside warm throughout the day. This is known as the greenhouse effect in which warm temperature is constant inside the greenhouse. The most common greenhouse gases are carbon dioxide and water vapour.
Using this concept, we can then explain how Earth works as with the greenhouse effect. Our atmosphere around our planet traps the heat from the sun and carbon dioxide in the air is able to trap the heat and keep Earth warm (which is a positive impact). However, as we carry out more burning and deforestation, the carbon dioxide level increases and it becomes more warm. Carbon dioxide traps more heat. This then causes global warming.
Read this website here!
5. Deforestation and reforestation
Deforestation is the removal of trees in a forest. This then lead to soil erosion and the increase of carbon dioxide in the air as there are no plants to take in carbon dioxide. Then, the temperature of Earth will increase and this creates global warming. But, we can rectify this by planting more plants to replace those we remove. This is called reforestation.
6. Global warming
Global warming is a worldwide issue now that when the Earth gets hotter and hotter and this affects living organisms, environment and our survival. When it is too hot, the ice at the colder regions such as the north and south poles melt away. This then cause the organisms at the habitats to die off as they cannot adapt to the sudden change of hot temperature. Also, this causes flooding as the sea level will rise with the ice turning into liquid water. Importantly, one action can set off a chain reaction.
Summary
In this topic here of Man's impact on the environment, we need to know the various negative and positive impacts and how these actions impact the environment and what we can do to overcome the problems.
Homework:
Science revision worksheet 1b (open-ended) to be submitted on Friday.
Last words for the day
The constant reminders each day to really study hard and strive for excellence should now sink into your head. I have my reasons for not pumping you with too much homework as I believe that homework should be done with quality and then gone through detailedly. I do not believe in giving you so much homework that you rush through and cannot cope. So, I need your help to be on your best behaviour and attention in class so that we have maximum time to go through the papers and complete the work. Work on your speed.
I am moving into the phase of revision now. Revision papers are given out already and very soon, the PSLE booklets will be gone through with you.
Now, your immediate action would be to revise for your oral examinations next Tuesday/Wednesday.
Head over to lead.com.sg to practise on some english practices.
Sincerely,
Mr Nelson Ong
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