CHEM NOTES

Hey i made some chem-notes on atomic model for final year revision sharing them here!

download them here

http://www.mediafire.com/?kbz9cxl8qc9se7n

Nutrient cycles???

Hey guys we only learnt about the carbon cycle what about the other cycles.

Let us take a look at the phosphorous cycle:

•Biogeochemical cycle

•Describes the movement of phosphorous through the lithosphere, hydrosphere and biosphere

•Atmosphere does not play signifincant role in movement

•Due to phosphorous based compunds are usually solids on earth

•Low phosphorus availability slow down microbial growth

•Proved in studies of microbial biomass

USE/CHARACTERISTICS:

•Essential nutrient for plants and animal in ions

•Limiting nutrient for aquatic organisms

•Forms important life sustaining molecules

•Remain mostly on land ,does not enter atmosphere

•80% used to make fertilizers

•Occurs as part of a phosphate ion

•Component of nucleotides

•Serve as energy storage within cells

•Linked together from DNA and RNA

•Double helix possible cause of phosphate ester bridge bind helix

•Make biomolecules phosphorus found in bones

•Function as buffering agent in maintain acid base hemostasis in body

Reflection

HAHAHA....

Reflection: The grueling term 3 have finally ended, ideas and thoughts start surfacing in my mind again about the subject science. There had been a great improvement for this term’s science lessons from last term. The class is now more cooperative with the teacher and behaving better and we are also catching up with the scheme of work. The remedial periods now after school have helped us a lot in answering our queries, at the same time having better understanding of scientific concepts and more practice on challenging questions. This term’s effective science lessons have also been clearly reflected in my science mean grade. I feel that I had certainly improved a lot from last term and can now focus more in class. Science lesson have also became more interactive with the usage of interesting videos. I hope that this trend can continue till our EOYs. I hope that the remedial consultation sessions can still be continued in term 4 so as to provide extra aid to students with slower understanding of scientific concepts like me. From term 1 to term 3, I felt that I have gradually developed from someone that hate science to someone that loves science.

Reflection

MMMmmm...

Reflection: After term two, I had many feelings within myself about science lesson and I would like to express it through the e-portfolio. Science in term 2 can be described with the word ”chaos”. Every science lesson there would be people using the computer, talking, walking about and shouting loudly. This had greatly disrupted the progress of our science lesson and we were unable to follow to the scheme of work. Furthermore it also disrupted my understanding of scientific concepts. The rowdy behavior of the class makes it hard to focus during lesson especially when the teacher is going through important concepts and questions with us. I feel that the class should be more cooperative with the teacher and it is only with cooperation learning can take place. Besides that I hope that there could also be a consultation period after science lesson so that we can clarify our question that surface during the lesson which the teacher was unable to answer due to time constraint. Lastly, I also hope that science lesson can be more interesting, interactive and also with joy. That’s what I think about science for term 2 and what I am hoping for in term 3.

Crazy fluids

wAlKiNg oN cUsTaRd

In some Chinese Martial Arts Drama Series, you may have noticed the characters in the shows can walk, run or even fight on water. Is this possible in the real life. The answer is no. Humans can't walk on water. We are too heavy to be supported by the surface tension of the water and not buoyant enough to float. But human can walk on fluids, something like custard.

Custard is a non Newtonian fluid, which means sometimes it has properties of liquids and sometimes it has properties of a solid. When you walk across the custard, you will be doing it quite fast and also impacting the custard quite hard, under those circumstances when pressure is exerted it behaves more like a solid and liquid. However when you stop walking or impacting the custard, there will be no pressure being exerted and this would make the custard behave more like a liquid. When it behaves like a liquid, you will sink into it. That is not all for this post, watch this video to understand more on what I am saying.

Mosquitoes vs Fish

Hey guys, I found something interesting about how to counter mosquitoes by introducing their predators (ecology).

Mosquito breeding is a big problem found in Singapore. Mosquito breed in practically every water body found. Some houses do not make the effort to maintain their ponds (like those in private bungalows), thus this had caused large numbers of mosquito breeding.

The most common method for people is to add anti mosquito chemicals to the water in the pond. The chemicals. firstly may not be really environment friendly and secondly they are not a long-lasting method. These chemicals can work up to five months depending on the dose.

Let me introduce a new long-lasting method, to solve the mosquito breeding problem in abandoned household ponds we could add a special type of fish which is related to guppies into the water, known as mosquito fish. In open water, this type of fish devours other fishes. However when put into ponds where mosquito breeds, they would be able to eat up the mosquito larvae. This type of fish reproduce at a fast rate, furthermore they are relatively cheap.


Buy some mosquito fish....

Reactions

Something about chemicalreactions.

Let me show you how the reaction takes place.

All of the alkali metals are notable for their vigorous reactions with water, and these reactions become increasingly vigorous when going down their column in the periodic table towards the heaviest alkali metals, such as caesium. Their chemical reactions with water are as follows:

Alkali metal + water → Alkali metal hydroxide + hydrogen gas

Alkali metals float on the top of the water as a very very hot ball, the size of the alkali metal is determines the effect of the reaction, hydrogen gas, which is quite flammable is released.(It looks like a rocket :D)

reflection on term1

This term had been a really busy term for me. For science, I can say that I had put in a lot of effort. I also devised a study plan for science. Firstly, read up on the set of notes that were issued in class. Secondly, use a mind map and re-organise the information in the notes. At the same time, this would also help you memorize the facts. By making and updating your own notes I think that it is a really effective way to study science. For this term, I did two revision in total for science and my hard work indeed paid-off and I got an A1. I would work harder next term and hope that I could maintain my performance in this subject.

fun stuff

Human limits

Yo! I had just read an interesting article on human LIMITS.

Lack of oxygen : normal people would pass out within two minutes, but with special training it is possible to hold our breath for 11 minutes

Lack of food : human can withstand 45 days without food, however there might be a drastic change in our body weight and we are likely to be killed by disease

Lack of water : every cell needs water, thus humans can at most survive for a week only when we do not replenish our body with water

Blood loss : after spilling 30% of the blood, humans could still survive, but when humans lose 40% of their, a immediate blood transfusion is needed, if not there is no chance for survival

Diving Deep : most people black out before 2 min and below 60 feet but the best free dive made was 282 feet

High Altitude : most people faint when they reach places at 15000 feet, but highland dwellers with bigger lungs and greater number of red blood cells are able to reach places of higher altitude

Hot air : Adults are able to survive for ten min at 300 degree Fahrenheit, but children succumb to lower temperatures

Cold Water : in a 40 degree Fahrenheit ice water, humans can barely survive for 30 min

Body Heat : heat stroke is irreversible when body temperature reaches 107.6 degree Fahrenheit

Take note of these human limits it may help you survive in harsh weather conditions!