[TR] Term 4 reflections

Its the last day of the school and the school holidays have officially begun. Well what a crazy year it has been, firstly what a crazy day it has been. I ate 6 slices of pizza today! 3 from my class's pizza party, and another 3 from my CCA's pizza party. :)

YUM.....

But seriously, what a crazy year it has been. My results went from good to bad then to good again. I'm really happy with my performance this year for Science. With the exception for term 2, I think I really did my best for all 3 terms. And most importantly, I had fun doing it. Having the opportunity to do an experiment a week, is not something every child gets, and I'm really thankful for it.

Even if my pride got the better of me in the middle of the year, I got back on my feet and it got me exempted for the year. It really paid off. And now, after some time deciding on which special program I should choose and whether or not I should take a Special Program in the first place, I think I finally know what it is. SMTP. I have a huge passion for science and discovery. And I can see that SMTP Science will really provide me with that opportunity to learn even more next year. Getting to the use the SRC, as well as engage in research is something I have always dreamed off.

Anyway, this is probably my last post of the year but the first post you see when you click on my blog, so I will make a handy content page. :)

This is the first post you should read

This is where you access all the IRs

This is where you can access al the other TRs

This is where you can access all the Biology posts

This is where you can access all the Chemistry posts

This is where you can access all the Physics posts

This is where you can access all the Geology posts

[IR] Candles

Well, again, this is not my usual post day, its a Sunday, not a Saturday, but, its my birthday today, so I thought I would write about something related to birthdays - candles. If you remember, my last post was way back in the 22nd of September and I said that it would probably be my last post before my termly reflection. Well you get a treat. So let's get right to the post.

So, how do candles work?
Candles really are an amazing lighting system -- the fuel itself is the package. There are two parts that work together in a candle:
The fuel, made of some sort of wax
The wick, made of some sort of absorbent twine


The wick needs to be naturally absorbent, like a towel, or it needs to have a strong capillary action. If you buy a length of un-waxed wick at a craft store and play with it, you will find that it feels like soft string and absorbs water very well. This absorbency is important in a candle because the wick needs to absorb liquid wax and move it upward while the candle is burning.


Paraffin wax is a heavy hydrocarbon that comes from crude oil. When you light a candle, you melt the wax in and near the wick. The wick absorbs the liquid wax and pulls it upward. The heat of the flame vaporizes the wax, and it is the wax vapour that burns.

The reason the wick does not burn is because the vaporizing wax cools the exposed wick and protects it. You may have seen the camping trick of boiling water in a paper cup. The cup does not burn because the water inside cools it. The liquid wax does the same thing for the wick.

Paraffin wax will burn on its own, but it is like cooking oil, motor oil and coal in that you have to get it very hot for combustion to begin. An oil fire is intense and very hard to put out. Paraffin is the same way. In a candle, this works great -- only the tiny amount of wax on the wick is hot enough to vaporize and burn.

[SR] Apple and the Post PC Revolution

Apple is undoubtedly one of my favourite companies in the world. Their culture of perfection, and simplicity is very well in sync with my own beliefs. So, from the very start I knew I wanted to do a feature article on their technology for my science eportfolio. So here it is.

There is one another thing you should take note of, since the exams are coming, I doubt I can squeeze in 5 posts for the month of September, so you will get one post a week for the first 4 weeks of September, leaving us with 4 posts for the month of September. Well, so far for all the months of school breaks, I have decided to go with a theme and write special reports on the theme, so this time will be no different. The theme chosen this time around is Apple and the Post PC Revolution, but you probably already knew that from the title. What is different this time around is that all articles are part of the mini series instead of including a mini series within the month. It will be a 4-part mini series.

So, a little bit of background, before we officially launch the mini series.

Its the year 2007, Steve Jobs announces the first iPhone.

The world has never seen anything like it before. A phone with only one button, and with a (then) giant 3.5" touch screen with revolutionary multitouch software. Allowing you to unlock the phone with a swipe of the finger, scroll through songs with the push of the finger. The crowd were absolutely blown away, but the tech "gurus" were less than optimistic about it, and its high price tag. Saying it was just going to be a luxury item for the super rich. No one could have predicted that it would go on to sell 4 million units in its first year. A year later, the iPhone 3G with the App Store was launched. Then another year later, the iPhone 3GS that was twice as fast. And then a whole slew of other companies came up with phones that looked almost identical to the iPhone. It became the norm. It revolutionised the whole mobile phone industry.

2010, Steve announces iPad.

Once again, the "gurus" mocked its name and continued saying it would flop. But flash forward 2 years later in 2012, the iPad has 67% of the tablet market -  a market Apple created themselves. Despite thousands of tablets being released every year, they are still no match for iPad. The same year, 2010, Apple introduced iPhone 4 which went on to sell 2 million units on its launch day. 2 million units in a single day.

WWDC 2011, Steve Jobs introduced iCloud. 

It automatically pushes all your content to all your devices keeping them in sync with each other. At the same time, the PC was dethroned as the digital hub for your digital life and replaced with the cloud.

These 3 products have really kickstarted the Post PC Revolution which Apple is spearheading. So over the next 4 weeks, we will find out more about the technology that made these products possible.

So... are you ready? Well before we go into that tomorrow, you need to know the tag to access all these posts, and the tag is AP. 

So interestingly, the 3 themes we have this year all have their tags start with A. AA for Animal Adaptations Month. AV for Aviation Month and now AP for Apple and the Post PC Revolution. Coincidence?

[TR] Term 3 Reflections

YAY! I feel just like how I felt when I got back my term 1 results. Only this time, I'm even happier because I topped the class. I got 43/45 for the test.

I'm so happy because in term 2 I said that I wanted to get back 42/45 again for term 3's test. And it turns  out, not only did I manage to meet that goal, I managed to surpass it!

The even better news? I heard that you no longer need A1s for all term tests for exemption in Science, all you need is an average above 80. And my average meets that with some room to spare, because of my awesome results in term 1 and term 3. I'm so happy.

I'm quite proud of myself because I said that I would pay a lot more attention in class and that's what I did to achieve this results. But, its not over, I can't be sure that I got exempted until I get the official certificate, but I remain optimistic.

[IR] Stem Cells

So yeah, that was a short introduction to stem cells.

• These, are probably, the most useful cell in multi-cellular organisms.
• In mammals, there are two main types of stem cells: embryonic stem cells and adult stem cells.

Before we get started, we need to know more about potencies in cells.

1) Totipotency:

• Is the ability of a single cell to divide and produce all the differentiated cells in an organism.
• Totipotent cells include spores and zygotes which are the initial cells formed when two gamete cells are joined by means of sexual reproduction.

2) Pluripotency

• Refers to a stem cell that has the potential to differentiate into any of the three germ layers:
• Endoderm (interior stomach lining, gastrointestinal tract, the lungs)
• Mesoderm (muscle, bone, blood, urogenital)
•Ectoderm (epidermal tissues and nervous system).

3) Multipotency

• Have the potential to give rise to cells from multiple, but a limited number of lineages.
• An example of a multipotent stem cell is a hematopoietic cell — a blood stem cell that can develop into several types of blood cells, but cannot develop into brain cells or other types of cells.

4) Other potencies

• They include ogliopotency and unipotency.
• Ogliopotency refers to the ability of progenitor cells to differentiate into only a few cell types
• Unipotency refers to a cell that has the capacity to develop into only one type of tissue or cell type.

So now, let's get down to business. So, as I was saying, In mammals, there are two main types of stem cells: embryonic stem cells and adult stem cells.

Embryonic Stem Cells

• Embryonic stem cells are pluripotent stem cells
• Derived from the inner cell mass of the blastocyst, an early-stage embryo.

• Embryonic stem cells are distinguished by two distinctive properties: their pluripotency and their ability to replicate indefinitely.
• They are able to differentiate into all derivatives of the three primary germ layers: ectoderm, endoderm, and mesoderm. These include each of the more than 220 cell types in the adult body.

Adult Stem Cells

• Adult stem cells are mutlipotent
• So they have limits to what cells they can develop into unlike the embryonic stem cells.
• However, there are pluripotent adult stem cells but they are rare and generally small in number

• However, there are pluripotent adult stem cells but they are rare and generally small in number
• But can be found in a number of tissues including umbilical cord blood. This is why parents are given the option of storing their babies’ umbilical cord blood, so if the babies develop cancer or other such diseases when they grow up, they can use these stem cells to save their child.

So, how can these stem cells be used for treatment of medical illnesses?

• Medical researchers believe that stem cell therapy has the potential to dramatically change the treatment of human disease.
• A number of adult stem cell therapies already exist, particularly bone marrow transplants that are used to treat leukaemia.

• In the future, medical researchers anticipate being able to use technologies derived from stem cell research to treat a wider variety of diseases including cancer, Parkinson's disease, spinal cord injuries, amongst a number of other impairments and conditions.

So, lets end off with a cartoon.

[IR] Double Rainbow All the Way

Rainbows are a phenomenon that has been widely recognized as a beautiful natural occurrence throughout the stone age and now we understand the physics of the rainbow.
A rainbow is an optical and meteorological phenomenon that causes a spectrum of light to appear in the sky when the Sun shines on to droplets of moisture in the Earth's atmosphere. It takes the form of a multicolored arc. Rainbows caused by sunlight always appear in the section of sky directly opposite the sun.
In a so-called "primary rainbow" (the lowest, and also normally the brightest rainbow) the arc of a rainbow shows red on the outer (or upper) part of the arc, and violet on the inner section. This rainbow is caused by light being refracted then reflected once in droplets of water. 
It is impossible for an observer to maneuver to see any rainbow from water droplets at any angle other than the customary one (which is 42 degrees from the direction opposite the Sun)

The light is first refracted entering the surface of the raindrop, reflected off the back of the drop, and again refracted as it leaves the drop. The overall effect is that the incoming light is reflected back over a wide range of angles, with the most intense light at an angle of 40–42°. The angle is independent of the size of the drop, but does depend on its refractive index. 

DOUBLE RAINBOW!!!

Although most people will not notice it because they are not actively looking for it, a dim secondary rainbow is often present outside the primary bow. Secondary rainbows are caused by a double reflection of sunlight inside the raindrops, and appear at an angle of 50–53°. As a result of the second reflection, the colours of a secondary rainbow are inverted compared to the primary bow, with blue on the outside and red on the inside. The secondary rainbow is fainter than the primary because more light escapes from two reflections compared to one and because the rainbow itself is spread over a greater area of the sky. A very dim tertiary rainbow, caused by a triple reflection of sunlight inside the raindrops, has been seen on rare occasions.

Supernumerary rainbow

A supernumerary rainbow—also known as a stacker rainbow—is an infrequent phenomenon, consisting of several faint rainbows on the inner side of the primary rainbow, and very rarely also outside the secondary rainbow. Supernumerary rainbows are slightly detached and have pastel colour bands that do not fit the usual pattern.

Reflected rainbow

When a rainbow appears above a body of water, two complementary mirror bows may be seen below and above the horizon, originating from different light paths. Their names are slightly different. A reflected rainbow will appear as a mirror image in the water surface below the horizon, if the surface is quiet. The sunlight is first deflected by the raindrops, and then reflected off the body of water, before reaching the observer. The reflected rainbow is frequently visible, at least partially, even in small puddles.

[IR] Fireworks - The Science

         Well fireworks to start with are the result of chemical reactions between elements, compounds or mixtures.They are used for mainly aesthetic purposes. The history of fireworks goes back to China but they were not really the fireworks we saw today...
         A long time ago, in a land faraway (actually it is not that far from Singapore...) the villages in China were always terrorized by a big, fat and ugly monster called "Nian". "Nian" always seemed to attack on the first day of the first month of the lunar calendar. One day, an ancient Chinese alchemist found out the magic (as it would seem at that time) of fire and realized its potential to ward off  "Nian". So that nest Lunar New Year, they all waited in their houses with firecrackers put out. And when "Nian" finally came, he was warded off quickly by the noise of the firecrackers and the villagers lived in peace ever since.
        Fireworks are a class of explosive pyrotechnic devices that are designed to burn with coloured flames or sparks. They take many forms to produce four primary effects- sound, light, smoke and floating materials. Fireworks are made out of 5 main components
-Fuel (To allow the firework to burn)
-Oxidizer (To feed oxygen for combustion)
-Mixtures of compounds or elements (For colouration)
-Chlorine (To strengthen the colour of the firework)
-Binder ( To hold the firework together)\



Fireworks come in many different colours based on the mixture and percentage of the compounds and  elements

Red	Strontium (intense red) Lithium (medium red)	SrCO3 (strontium carbonate) Li2CO3 (lithium carbonate) LiCl (lithium chloride)
Orange	Calcium	CaCl2 (calcium chloride)
Yellow	Sodium	NaNO3 (sodium nitrate)
Green	Barium	BaCl2 (barium chloride)
Blue	Copper	CuCl2 (copper chloride), at low temperature
Indigo	Cesium	CsNO3 (cesium nitrate)
Violet	Potassium Rubidium (violet-red)	KNO3 (potassium nitrate) RbNO3 (rubidium nitrate)
Gold	Charcoal, iron, or lampblack
White	Titanium, aluminium, beryllium, or magnesium powders

Here is a stellar fireworks display:

Fireworks at Singapore Flyer Opening

Burj Dubai Opening

May not explain much science, but at least it looks pretty :)

[SR] Forces of Flight

There are four forces of flight -drag, thrust, weight and lift. All four play an important role in how planes fly.

 Drag

As the airplane moves through the air, there is an aerodynamic force present. The air resists the motion of the aircraft and the resistance force is called drag. Drag is directed along and opposed to the flight direction. There are many factors that affect the magnitude of the drag force including the shape of the aircraft, the "stickiness" of the air, and the velocity of the aircraft. We collect all of the individual components' drags and combine them into a single aircraft drag magnitude. Drag acts through the aircraft center of pressure. The drag of the air makes it hard for the plane to move quickly. Another name for drag is air resistance. A streamlined shape slips smoothly through the air. 

Thrust

To overcome drag, airplanes use a propulsion system to generate a force called thrust. The direction of the thrust force depends on how the engines are attached to the aircraft.
On some aircraft, such as the Harrier, the thrust direction can be varied to help the airplane take off in a very short distance. The magnitude of the thrust depends on many factors associated with the propulsion system including the type of engine, the number of engines, and the throttle setting.
For jet engines, it is often confusing to remember that aircraft thrust is a reaction to the hot gas rushing out of the nozzle. The hot gas goes out the back, but the thrust pushes towards the front. Action <--> reaction is explained by Newton's Third Law of Motion.

Lift

As the aircraft moves forward into a stream of air, the wing deflects the air. Some of the air moves to flow above the wing while some of the air moves to flow below the wing.
The wing is curved to help the air that flows above the wing move more quickly than the air that was able to flow below the non-curved bottom of the wing. This curve is called an aero-foil wing.

The air that is moving more quickly above the curved wing starts to put less pressure on the wing while it adjusts to its new stream. Meanwhile, the air that is moving at a consistent speed below the wing maintains its rate of pressure. This quick differential produces lift. The higher air pressure pushes the wing upward into the space where the air pressure is lower.The distribution of lift around the aircraft is important for solving the control problem. Aerodynamic surfaces are used to control the aircraft in roll, pitch, and yaw.

Weight

Weight is a force that is always directed toward the center of the earth. The magnitude of the weight depends on the mass of all the airplane parts, plus the amount of fuel, plus any payload on board (people, baggage, freight, etc.). The weight is distributed throughout the airplane. But we can often think of it as collected and acting through a single point called the center of gravity. In flight, the airplane rotates about the center of gravity.

The motion of the airplane through the air depends on the relative strength and direction of the forces shown above. If the forces are balanced, the aircraft cruises at constant velocity. If the forces are unbalanced, the aircraft accelerates in the direction of the largest force.

[SR] Marvels of Aviation B787

Firstly, welcome to the 3-part mini series Marvels of Aviation, to see the other articles in this series, click the links above.

Aviation. The youngest mode of transportation at just over a 100 years old, but it has since become the premier way to travel long distances. 3 aircraft have changed commercial aviation and have contributed greatly to the advancement of technology for aircraft in the future. This is Marvels of Aviation.

Well, let's get started with a disclaimer. The 3 aircraft that I have chosen are for commercial aviation only, simply because I prefer the look of commercial aircraft to military aircraft.

So, today, let's discuss the Boeing 787. Or what Boeing dubs, the Dreamliner.

It all began in 2001...

The global airline market was upended by the September 11, 2001 attacks and increased petroleum prices, making airlines more interested in efficiency than speed. The airlines in the United States, potential customers of a Sonic Cruiser Boeing was developing, were the worst hit. This caused Boeing to scrap the Sonic Cruiser plan and begin what was known as the 7E7. Boeing wanted to replace its entire airliner product line, in an endeavour known as the Yellowstone Project. The 7E7 was the first stage of that project. It was to replace its existing 767 and 777 product lines. The 7E7 is said to be the most efficient aircraft Boeing has ever created. The "E" was said to stand for various things, such as "efficiency" or "environmentally friendly"; however, in the end, Boeing claimed that it stood merely for "Eight". Boeing later changed its name to 787 in 2005, and it was finally rolled out in 2007, by which time it had reached 677 orders; this is more orders from launch to roll-out than any previous wide-body airliner. On October 26, 2011, the 787 flew its first commercial flight from Tokyo Narita Airport to Hong Kong International Airport on All Nippon Airways. But what made it such a marvel?

Its design. The 787 is primarily made out of composite materials.  Its materials, listed by weight, are 50% composite, 20% aluminium, 15% titanium, 10% steel, and 5% other. So what exactly are these composite materials?

Each 787 contains approximately 32,000 kg of carbon fibre reinforced plastic (CFRP), made with 23 tons of carbon fibre. Carbon fiber composites have a higher strength-to-weight ratio than traditional aircraft materials, and help make the 787 a lighter aircraft. Composites are used on fuselage, wings, tail, doors, and interior. This allows it to become Boeing's most efficient aircraft to date.

Boeing also designed its engines to reduce noise.The engines have have a toothed edge and Boeing calls them chevrons. It allows for a quieter mixing of exhaust and outside air.

Boeing also designed the interior to look and feel better for passengers. They designed the entrance to feel a lot more open so passengers won't feel as cramped. They have also widened the aircraft at eye level so it feels more roomy and spacious for passengers 

They also have cool windows that can tint with a press of a button. Replacing window shades, these cool windows have 5 different shade settings for passengers to personally adjust.

I'm sure that you'll agree with me after reading all these innovations the 787 has pioneered. And it truly is a marvel of aviation.

[SR] Jet Engines

        When humans first observed how birds fly in the sky, they realized that it not only took the birds their light weight, and wings to get them flying, they needed speed. And since the day the Wright brothers built the Wright Plane, the propulsion of aircraft has also evolved, and today, the propeller that had propelled once propelled aircraft into the sky, has been replaced by a bigger, more efficient and faster alternative, the jet engine.

        Aviation is the youngest of all commercial transport and has the fastest growth as well. Many of us has flown on an aircraft before, yet many of us do not understand how the jet engine works. It is a fairly simple concept really, the idea is to suck air in and blast it out at higher speeds, but the technology involved with it is far more complicated.

        To start with, there are 4 types of engines, turbojet, turbofan, propfan, and turboprop.

Propfan

Turbofan

Turbojet

Turboprop

        

       A jet engine works by first sucking in and compressing the surrounding air through the axial compressor. The axial compressor comprises of both moving and stationary blades. The moving blades suck in the air while the stationary ones guide the air and ensures the air enters at the right angle. Then the air flows into the compressor which rotates at very high speed adding energy to the airflow and at the same time squeezing  it into a smaller space. They can compress the air in a 44:1 ratio. The air then moves into a combustion chamber where fuel is mixed in with the air and is ignited and the air would flow at a much faster speed. The temperature of this air would melt the turbine so the compressor directs some air into through a separate channel and this cooler air acts as a coolant for the jet engine. The turbine is another series of blades and it would make the air flow faster. The gas then exits through the nozzle and blasts the aircraft forward.  

Reverse Thrust

As the name implies, it literally sucks air in from the back and blasts it out from the front. Have you ever noticed when landing, a loud roaring of the engine can be heard, that's reverse thrust taking place, it slows down the plane considerably for landing.

Thrust reversal, also called reverse thrust, is the temporary diversion of an aircraft engine's exhaust or changing of propeller pitch so that the thrust produced is directed forward, rather than aft. This acts against the forward travel of the aircraft, providing deceleration. Thrust reversers are used by many jet aircraft to help slow down just after touch-down, reducing wear on the brakes and enabling shorter landing distances. It is also available on many propeller driven aircraft through reversing the controllable pitch propeller to a negative angle.