Important annoucement - Chemistry

Dear 3E2,

See you guys for extra lesson on 5 May (Wed) 2.30pm.

Jia you in your exam preparation!

Eat well and sleep well too!

Mrs. Yeoh

Wednesday, May 19, 2010

Physics (edited) by : Poh Wan Jie (17)

Q1) From the burning of fossil fuels to produce energy, green house gases are emitted which contributes to Global warming or the Green house effect. From the video, name some of the green house gases emitted by humans.

The green house gases emitted by humans are Water vapour , Mathane , Nitrogen Oxide .

Q2) How has global warming affect Singapore over the past 20 years? (Search the internet)

The planet faces great menace which is occurred by global warming. Global warming is an observable fact, but no one understands the level of its power on climate change. Due to the climate changes we all have now big problems like summers are getting very hot than ago year, winters are frieze than of previous years, and bad incident happens gradually. Further affect of Global warming is on to our coasts, our health, our energy and water resources, our agriculture, our transportation infrastructure, and our recreational resources due to the global warming.

Green house gases
There are numerous global warming affect on our climate, but the major affect is green house gases like carbon dioxide, methane, and nitrous oxide are playing vulnerability on our climate in the present times. There has been a noticeable rise in the average temperature of planet in the past century. This rise in temperature is credited to the effects of global warming brought about by the increase of greenhouse gases in the atmosphere. These green house gases catch heat in earth’s atmosphere and thus result in increasing the temperature of earth. They catch warmth release by the sun, heating earth. This process will make life on the planet possible. Natural greenhouse gases like carbon dioxide, methane, and nitrous oxide have always been in the atmosphere. Lack of this gas, world’s average temperature would be a chilly-18 degree Celsius. With the help of greenhouse effect we can enjoy an average temperature of 14 degrees on our planet.

Carbon dioxide (CO2)
Carbon dioxide is the number-one reason for climate change. The major source of carbon dioxide is the power plants. These power plants emit large amounts of carbon dioxide produced from burning of fossil fuels for the purpose of electricity generation. Carbon dioxide is the second-most important greenhouse gas behind water vapor. Methane and ozone are more efficient, but have less effect on climate change. Due to industrial revolution, the average amount of carbon dioxide in the atmosphere has been increased by nearly 40 percent. This increase in CO2’s share of the atmosphere is mostly due to burning fossil fuels, deforestation and industrial production. Mostly humans produce around 32 gig tons of carbon dioxide every year, fifty percent stay in atmosphere and remaining are absorbed by oceans and plants. The result of the increasing amount of carbon dioxide in the atmosphere is greenhouse effect and, next climate change.

Sea level rising
It depends on which greenhouse gas increase setting is used (high or low) for projected sea-level. Sea level has been rising at an average rate of 1.7 mm/year (plus or minus 0.5mm) over the past 100 years. It is considerably larger than the time averaged over the last thousand years. Sea level rise is projected to be anywhere from 0.18 (low greenhouse gas increase) to 0.59 meters for the highest greenhouse gas increase set-up. This increase is due to mainly thermal expansion and contributions from melting alpine glaciers.

Oceanic circulation changing
The oceans absorbed fifty percent carbon dioxide but highest levels of CO2 have led to ocean acidification. Furthermore, as the temperature of the ocean increases, they become less able to absorb excess CO2. Global warming is projected to have a number of effects on the oceans. Likerise in sea levels due to thermal expansion and melting of glaciers and ice sheets, and warming of the ocean. Other probable effects take in large-scale changes in ocean circulation.

Global Warming

Q3) You have just studied heat is transferred in 3 ways, conduction, convection and radiation. And you have some ideas on how to keep the classroom COOL in a hot and sunny day yet cutting down on the energy usage! * so air-con is out of the option *




We can paint our classrooms in colours or white colour that is a good reflector of light and also radiates heat quickly. This way we would not feel so much heat. Must not paint the classroom wall in black colour as it absort and emit heat very quickly . This way , it makes us feel hotter .We can use curtains to block out the heat.We must not close the doors of our classrooms so that air can come in. Otherwise, the classroom will be very stuffy and we would not feel comfortable studying. we should change all the bulbs into the energy-saving bulbs. This would obviously save the energy that is being used. With all this , We are able to study and learn well in an conducive enviroment !

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