Electrolysis in batteries

Seal Lead Acid batteries have a long history of being one of the most environmentally friendly resources on the free market and are actually "greener" then soft drink cans, beer cans, newspapers, glass bottles, and tires. Indeed lead-acid batteries are an environmental success story of our time. More than 97 percent of all battery lead is recycled. This is almost twice as much as aluminum soft drink and beer cans, newspapers, glass bottles and tires. In fact lead-acid batteries are the most recycled consumer product of our time. How are lead acid batteries recycled and reused in brand new batteries. What is the recycling process of lead acid batteries? Let's find out.

Lead acid batteries are transported via trucks to recycling centers. Once at recycling centers batteries are broken apart in a hammermill, which is a machine that hammers the battery into pieces. At its most basic level a hammermill is a steel drum that contains a cross-shaped rotor. On the rotors are mounted hammers that pivot when the rotor spins. When the rotor spins the hammers swing and when the battery fed into the drum the batteries broken into pieces.

Once broken the batteries components are separated into 3 categories:

Plastics

Broken pieces of polypropylene plastic are collected, washed, blown dry and sent to a plastic recycler. At the plastic recycler the broken pieces of polypropylene are melted at the plastics correct melting point (or glass transition temperature (Tg), which is the temperature at which a polymer changes from hard and brittle to soft and pliable). Then the molten plastic is passed through a machine called an extruder that shapes the molten plastic into pellets which are then sold back to battery manufacturers to begin the new battery's manufacturing process.

Lead

The lead acid batteries lead grids, lead oxide and other lead parts are cleaned and then heated to 621.5 degrees Fahrenheit - leads melting point. After the lead reaches its melting point the molten lead is poured into ingot molds. The leads impurities, known as dross, floats to the top and subsequently scraped away and then the ingots sit there until they are cooled. After cooling the ingots are sold back to manufacturers for use in new lead plate production.

Electrolyte - Sulfuric Acid

Spent battery acid can be neutralized using an industrial grade baking soda compound. After neutralization the acid turns into water, treated, cleaned to meet clean water standards, and then released into the public sewer system. Or another option would be to convert spent battery acid into sodium sulfate, which is used in laundry detergent, glass and textile manufacturing. Considering that a typical battery recycling plant recovers 10,000 tons of lead, about 4000 tons of sulphuric acid, and can produce about 6000 tons of sodium sulphate - there is definitely some merit into this conversion process.

Spaced Learning

You spend an hour at study, then fifteen minutes at a "break," another hour at your work, another break, and another hour of study, you will have learned more, and memory of the learning will last longer, than if you spend three or even four--straight hours at work.

Perhaps this is due to the reverie in which you are bound to indulge during the break period, reasoning out in your own thoughts the things you've been memorizing. Or, perhaps your mind simply begins to wander when you press it for too long periods of time. At any rate, spaced learning really does work ... try it. Studying for several short periods of time, with intervals of relaxation, generally produces longer-lasting memories than does one long, intensified study period.

Fringe benefits of spaced learning

A peculiar trick which your mind occasionally plays is remembering more of something some time after memorizing it, than very shortly after completion of the memory task. This seems to be a direct contradiction of the memory curve, but it's a very specialized case.

Soon after you've completed a turn at the books, you'll be able to remember a certain portion of the material you've covered, right? But, a few hours, or a day later, when you've spent a little time thinking about the subject, a few points which might have slipped your immediate memory will come to your attention through pattern and association with the related points which you have been able to remember. So, in effect, you are remembering a little bit more than you actually learned at the time of study.

This phenomenon might be a delayed memory of the "forgotten" material's actual position on the page, or a belated understanding of the words which at first you failed to understand, but later found rational in the light of your thinking about the entire subject.

Of course, this article is just the beginning. To discover how to master your exams in no time, visit http://www.secretstudyskills.com and grab your free 101 Study Tips. You can find out all about it by clicking here

Fossil Fuel

Can you imagine what life would be like without the use of fossil fuels? Let me start by explaining a little about what fossil fuels are.

In general, Fossil fuels are layers of plants and animals which have died millions of years ago, compressed and buried deep into the earth, through time to form sedimentary rock, such as coal, and liquid hydrocarbons such as oil or gas.

Coal is one of the first fossil fuels known to man, as has been used for a heating source, dating back to early 1600's. Since its discovery, we have found many other uses, such as powering steam driven locomotives, and today is used in factories to help produce steel, concrete, paper, plastics, and most importantly "Electricity".

Oil was said to be discovered by the Native Americans. This oil was found seeping to the earth"s surface, and was used for medicinal purposes. The first successful oilwell was drilled in Pennsylvania in 1859. This oil which was extracted, would find many uses, such as lamp oil. lubricants, and would later be used to power automobiles, trains, plane's, and is still used for these and many other things, to this present day.

Natural gas was basically discovered in the same manner as oil, seeping up through the earths surface, producing the same foul smell comparable to rotten eggs. This resource once contained would be used also for lighting, cooking and heating, and today has globally become one of our main sources of heat.

So ask yourself, could we live without these precious fuels? What would our world be like if these resources had depleted and became non-existent? Each and everyone one of us uses fossil fuels, and the demand and production grows larger everyday. What if rising prices of these precious commodities becomes unaffordable to the average working class? Everyone in this world knows that prices for oil and gas are already increasing at an alarming rate, with no end in sight. Until some one discovers an alternative fuel sources, well fact is fact, we will always be dependent on fossil fuels.

On a positive note, perhaps the rising prices in todays world is a sign that something new is around the corner. Governments and oil companies may be mass producing while the demand is still there. Maybe they know something we don't. Transportation counts for 70% of all the oil we use and now the transportation industry is starting to evolve into a new era with the production of the hybrid vehicles. This is a very positive sign, and could be the stepping stone for many, to increase awareness of how the extensive use of fossil fuels, is impacting our environment today.

To conclude, "Fossil Fuels", are a very important ingredient in our every day life, and we will always be dependent on them, but also new doors are being opened to lessen that dependency, and maybe one day the answer to my question, Can you imagine what life would be like without the use of fossil fuels? "Yes".

Writing and Communication

Language, as people say, is just a part of communication. In turn, writing, like speech, is one of the things we can do with language.

Writing, in any form, has the job of conveying information and meaning from a writer to an intended audience, or readership, for a particular purpose. The form it takes is quite various, and is to do with the medium or media in use.

Students have to demonstrate to their supervisors in an essay or dissertation that they have mastered its subject. Business organisations need to attract the attention and patronage of their customers through very brief radio and television ads, or, increasingly, through banner or pay per click (PPC) ads, online. Best men continue to address 'dearly beloved' audiences with not a little trepidation, but a carefully prepared and hopefully well rehearsed speech. The variety of writing is endless.

Writing then, is any planned, and structured, language-based communication, designed with an audience, a particular purpose, and a medium or media in mind. Its special significance - distinguishing it from more casual or spontaneous uses of language - is that it functions in the absence of its author. We do not need a Walton or a Sainsbury to tell us in person that their latest offers are too good to miss. Likewise, a well written research paper from the 1950s may reveal its author's errors of understanding, or lack of data, but will leave us in no doubt as to their way of thinking or rationale.

The reason authors or publishers can leave us to decode their messages is our community of language, values, cultural norms and references. So long as a piece of writing fits in well with those things a particular audience shares in common, the communication has a good chance of doing what its author intended. To get this right, the writer has to recognise the context in which they are writing, and plan the attributes of their writing accordingly.

The attributes of writing

We have already alluded to several different domains of writing (e.g. education, business). Depending on where we are working, media selection and/or document type(s) selection will be more or less automatic. In education and research, though there may be local differences in format and editorial preferences, the accepted or conventional forms of essay, dissertation, or thesis, paper, and article are well known and understood. Professionals are often required to produce bids, proposals, or pitches, which sometimes take a shape prescribed by the sponsor of the project, and are at other times left to the discretion of the authors.

In business organisations however, where customers, employees, investors, and other stakeholders have to be communicated with, at different times, for different reasons, and where some activities - e.g. brand building - call for integrated media selections as part of a coordinated campaign, these choices will be far more discretionary. Each piece in the jigsaw, however large or small, is a structured communication, requiring careful planning and execution.

All of the most effective communications are planned at the level of the individual execution or document (whether a thesis, brochure, or webpage).

Decisions on structure and layout are very important. Subject to the guidelines offered (e.g. word count, running time etc), one choice of structure over another can do much to affect 'standout', readability, look and feel. On some occasions, sections should be used to break up a whole into manageable parts. Perhaps these are better left undeclared or unseen (though they may have been used to write the piece); perhaps very obvious signposting is an advantage.

The use of language itself is more complicated a matter than it first appears. Style, register, tone of voice, and diction all need to take into account the positioning of the author or publisher, given the audience, the objectives of the communication, and the medium. A more or less formal style might be appropriate. Words and phrases need to be chosen with care, asking more or less of the reader, and creating a particular sort of impression.

A similar point needs to be made in relation to idiomatic words or phrases and other culturally-specific references.

Proper sentence construction follows on from choices about style and register, subject to the proviso that voices and tenses should be kept consistent as far as possible. Grammatical errors should be avoided, except at the expense of stilted English; 'this is the sort of bloody nonsense up with which I will not put', said Churchill.

Finally, spelling errors, typographical errors, or 'typos', and other production errors need to be corrected. Whilst production errors do not necessarily impede a communication's effectiveness, their risk and potential cost tend to vary with the audience. The indignation of a lay readership over a journalist's or editor's fallibility may not stop it from enjoying a piece, or continuing to take a newspaper. On the other hand, a large procurement function trying to form an overall impression of the likely competence, reliability, and accuracy of a professional firm, may, whether consciously or not, look less favourably on the production errors in a technical consulting bid.

Good writing

To recap then, writing is any structured, language-based communication, designed for a particular purpose, with an audience and medium in mind.

Good writing is writing which delivers the objectives of the communication, reaching and affecting the intended audience in the desired way, as far as possible within the selected media.

DIY FunScience Projects

PS: These Fun science projects should be done with adult supervision.

The first fun science project is called "The Balloon Inflater"

MATERIALS:

A carbonated soft drink in a bottle, a balloon, and a twist tie from a bread or a garbage bag.

WHAT TO DO: 1. Place the balloon over the mouth of the bottle and securing it to the bottle with the twist tie. 2. Have the adult hold the bottle and place their thumb over the mouth of the bottle covered by the balloon. 3. Now shake the bottle for five seconds and release your thumb. 4. The balloon fills with carbon dioxide that was dissolved in the soda pop. That's why they are called carbonated drinks.

This is a great fun science project that can give you that A you want in science class! Here is another great science experiment that anyone can do .

THE BALLOON ROCKET

MATERIALS: A balloon

WHAT TO DO: Simply blow up the balloon. Then, holding it between you thumb and forefinger, let it go and watch it fly.

EXPLANATION: You already know that the air escaped from the opening in which you blew up the balloon. You also noticed that the balloon flew in the opposite direction - this is action and reaction. The first force, air escaping, is the action. The balloon moving in the opposite direction of the air is the reaction.

We use this principle everyday. We push down on a chair to get up. We push our feet to the back to walk forward. A basketball pushes down onto the floor just before it bounces. You can probably think of many other examples.

I hope you have enjoyed these fun science projects. Please remember that these science experiments should be done with adult supervision.

Success Story & a new contributor

click on the picture above for the full version of the article

In this brief post today, we welcome a new contributor to learnsg.blogspot.com, Wenchuan. As documented above as extracted from Temasek Poly's newsletter, he is a young techno-whiz and a student under the diploma in cyber & digital security and was originally from Coral secondary.

He is an example to all that if u have the passion and the interest in a particular field, you can excel no matter where you from or what others feel. As a friend of him, we know he has the optimism to be successful and he shall continue to motivate others.

Graphs Transformation

Pls click on the above pics for the full size

Also pls note that the order of TSRRST is also applicable for both the forward & backwards....meaning for eg. (backwards) to get y=f(x) from y=D + Cf (Bx + A), we will still start wif translation (T) ferst in the brackets by getting rid of A first by forming the eqn y= D + C f(Bx + A -A). Hence, the order still follows just that everything is by eliminating the form to get back y=f(x).

How to remember what sort of transformation to do?

Simple, always remember that those transformation along the x-axis or those that are in the brackets are always opposite of wat they meant. For eg in translation, y=f(x + a) means a translation of a units in the negative x-axis direction (to the left by a units // to x-axis) while y=f(x-a) means a translation of a units in the positive x-axis direction (to the right by a units // to x-axis).

For scaling involving the x-axis it is always a reciprocal of the number. For eg, y=(2x) will mean a scaling along the x-axis by 1/2 times. If its y=(Bx), it will be a scaling along the x-axis by 1/B times meaning multiply the x-coordinates by 1/B. For reflection involving the numbers in the bracket like y=(-x), it means a reflection about the y-axis. In summary, it can be noted that any transformation in the bracket is always the opposite of what is meant (for translation), a reciprocal of the number (for scaling) & about the opposing axis (for reflection). Simply put, anything in the brackets is about OPPOSITES.

For those transformation involving outside the brackets or involving the y-axis are quite straight forward because they are usually written to be exactly what it means. For example a translation of y=f(x) + a means a translation of a units in the positive y-axis direction (move up) n the reverse for y=f(x) - a means a translation of a units in the negative y-axis direction (move down). For scaling, there is NO RECIPROCAL FORM NEEDED, when it is written as y= 2f(x), it simply means scaling of factor of 2 units along the y-axis meaning just multiply the y-coordinates by 2 NOT 1/2! Only reflection still follows the general rule of being the opposite whereby y=-f(x) actually means a reflection about the x-axis. Simply put, anything out of the bracket is straight forward and is all involving the y-axis EXCEPT for REFLECTION!!!

After mastering the transformation for graphs, it becomes quite standard for questions involving graphs transformation. Just ensure that there are no carelessness.

Mechanisms 1

Here are the mechanisms for 3 types of reactions. Free Radical Substitution for alkanes, Electrophilic Substitution for alkenes and Nucleophilic Substitution for Halogenoalkanes/Alkyl Halides.

Alkanes mainly go through Free Radical Substitution (FRS) reactions, combustion as well as cracking. Since i have not included any mindmaps on alkanes, i shall proceed to describe more about alkanes for our syllabus. Hydrogen atoms are substituted by halogen atoms in FRS.

Combustion reactions for alkanes have a general equation of:

C_xH_y + ( x + y/4) O₂ (g)→ xCO₂ (g) + (y/2) H₂O (l)

Typical alkane questions would usually involve the application of this equation so i think it's important to memorise it. There will be clues to helping you find the values of x and y in the equation. One particular type i noticed is that they like to do combustion then run the resultant gas through limewater to remove the CO_{2. From there, just determine the number of moles of CO2} and you have found the value of x! Note that water formed is in liquid state, not gaseous state in the equation.

Another reaction to remember that alkanes undergo is cracking, which involves the breaking up of a large molecule to smaller molecules. Hydrogen gas is produced from cracking reactions.

For more information about Halogenoalkanes or Alkenes, please refer to the Chemistry section and search for a post with the appropriate title.

Mechanisms for the 3 reactions:

I've got one arm longer than the other!

Tired from studying? Looking for cheapthrills? Look HERE!

It would be weird to see one arm shorter than your other arm wouldn't it? Try this!

1) Stretch both arms out. Ensure they're of equal lengths

2) Bend either arm (your choice) back and forth as if you're lifting invisible weights for about 30 seconds. (Rmb to do this for only ONE arm)

3) Stretch both arms out and check their lengths. One arm should be longer than the other now!

Juice stains

Did you know?
Sometimes we spill juice on our shirt and have a tough time scrubbing them out. What do you do?!
Try using milk to make the cleaning easier! Lipids in milk can help "loosen" the juice from the shirt to make the cleaning easier.

Iodoform test

The iodoform test (or tri Iodomethane test) is used to identify the presence of 2 particular structural units:

1)RCH(OH)CH₃

2)RCOCH₃

*R denotes H, alkyl or aryl group

In positive tests, the reaction will produce a yellow precipitate of CHI₃.

Equations:

*Click on picture for a clearer and bigger view
Any compound which contains the above mentioned structural units will result in a positive iodoform test. Ethanol is the only first degree alcohol to give a positive iodoform test.

Learning Biology with a Passion

Why learn Biology?

Everyone has to read a manual someday.. whether its a new electrical appliance or your new handphone, everything's accompanied by a little booklet which desires to be read..

Biology is that little booklet to life..

What better manual would you read than the one that tells you how your body operates? The passion for learning Biology comes from realising the need to know how your amazing body is designed.

Studying Biology is often seen as memorising parts and pieces of the body... but do we really need to know all that? I personally feel it is more important to know the function of the body parts- simply because when one can understand the function, one can understand why the part is named so.

Ultimately, the career prospects that Biology offers is often misunderstood as being a Doctor a Brain surgeon or a lab person. But in reality, many biologist don't find place in these careers. They settle in other professions because their study of biology helped them realise their interest for their profession.

When you know your physical self well enough, a greater desire to understand the mental and ultimately spiritual self will arise. This is the reason why the debate over evolution's credibility is always heated, and will be explored in issues to come.

Simply put, the study of biology is practical because, if one studys and not Mugs (studying without thinking), one will defintely have to think and consider the meaning of life. And it often calls for every biologist to take a stand: for evolution or against evolution. To believe in science, or not to. This questions will satisfy the deepests of all insecruities life could bring.

I sincerely hope I have depicted the essense of studying biology as one of purpose, and not of mindless memory work. Indeed, the human boday and mind is the greatest secret anyone can behold!

Aldehydes and Ketones (carbonyl compounds)

Aldehydes and ketones are carbonyl compounds which undergo Nucleophilic Addition. The oxygen atom bonded to the carbon is electronegative, hence, the C atom becomes slightly positive. The slightly positive C atom is thus the target of nucleophiles. It is easy to remember the reactions that aldehydes and ketones undergo. The most important thing to remember for this chapter is the identification of aldehydes and ketones. This is done so by carrying out a variety of tests which you have learnt in the syllabus. It is also important to be able to draw the compounds that are formed when the respective tests are carried out, especially for Brady's test. I have not included the equations for the Iodoform test clearly in the mindmap below. Do not that the equations of the Iodoform test are just as important to memorise.

How to remember the special angles without the need to memorise or use the calculator

In math, there are group of angles known as special angles. They are 0, 30° (p /6 ), 45 ° ( p/4), 60° (p /3) & 90° (p/2) . These angles are usually needed in math topics such as trigonometry and complex numbers. Usually a calculator can be used however some answers require candidates to give it as the exact form meaning as a fraction. In this case there is no other way than to derive the sin, cos or tan of the special angles which often means memorising. However, there is a quicker way to derive it other than memorising as shown in the table below.

The key to using this type of table is simply the order in which for sinq is from left to right which is from 0 to p/2 radians with the exception that at 0 radians...the sin must be 0. From p/6 to p/2 radians onwards, the sin for that angle will be a fraction of denominator 2 with the numerator, the square root of 1 to 4 corresponding to the respective consecutive special angles. Obviously, some of the fractions can be simplified. Now once, the sin of the number can be derived, to find cos of the special angles is the opposite or reverse order from right to left. Whatever respective numbers that you have written for the sin q from left to right is now the cos q of the angles from right to left. For example, sin 0 = cos p/2 & sin p/6 = cos p/3 . Hence, it is very simple, to derive both sin & cos of the special angles. To find the tan of the special angles, you just have to know the formula that tan q = sinq / cosq and then you can use your already find the tangent based on the sin & cos of the corresponding angles that you have derived earlier. If you are used to the table, it can saved you time and as you get familiar with the table, you can sketch the table by around a min.

Does this table works for obtuse angles or larger angles?

As long as the angles can give basic angles which are the special angles, it will work. However, you must remember the quadrant rules,in which in the 1st quadrant all the Sin, tan & cos are positive, 2nd quadrant where only the sin is positive, the 3rd quadrant where only tan is positive and the 4th quadrant where only the cos is positive. I will illustrate with an example, 135° , the basic angle here is 45° and this angle lies in the 2nd quadrant and it happens that the basic angle is also a special angle. If you want to find the cosine it will be a negative since only sin is positive in this quadrant. So, based on the table, we find the cosine corresponds to 45° in the table and then add a - in front due to quadrant rule explained earlier on. This will give you the correct exact cosine of 135°. It also works for any other angles in the other quadrants as long as the basic angles are the special angles.

This table is quite useful as you can also use it for the inverse of sin, cos & tan to find the specific special angles. So really, it is useful if you guys could master this table.

Halogenoalkanes (alkyl halides)

Halogenoalkanes, otherwise known as alkyl halides, consists of one or more halide atoms bonded to a carbon. This is represented by R-X in the mindmap, where R is a carbon atom while X is a halide atom. Alkyl halides undergo 2 types of reactions, mainly Elimination and Nucleophilic Substitution. In Nucleophilic substitution( N.S), the halide atom is substituted by a nucleophile. Nucleophiles are molecules/ions with at least a bond pair. Common nucleophiles include cyanide ions, hydroxide ions and ammonia.

Summary of Alkyl Halide reactions:

Information in 1, 2, 3 steps!

To use this website more efficiently, here are some guidelines to make your search for information faster. The sidebar contains a categorial archive with various subjects under it.

1) Click on the desired subject you want to look at. Eg. Chemistry

2) Press (ctrl + F) to bring up a search box with your browser

3) Type a detailed word(s) which best describes what you are looking for. Eg. Alkenes. This will bring you to the post about alkenes.

There you are. Searching made easier. I hope the information will be useful.

Katakana/Hiragana table

Here for a quick post. This is the Katakana and Hiragana table. It is used in the Japanese language for writing. What else needs to be said. Refer to the table and start writing Japanese now! =)

As usual, please do not republish this image without permission.

Hydroxy Compounds

Hydroxy compounds basically have the functional group -OH. The syllabus currently requires us to know the reactions for alcohol and phenol compounds. Alcohol is able to undergo oxidation while phenol is not able to due to strong bonds between -OH and benzene. Do note that the use of a strong or weak oxidising reagent will result in a different compound being formed from alcohol.

Phenol is able to undergo electrophilic substitution (Different from electrophilic addition in alkenes). As the name suggests, electrophilic substitution involves substitution. In phenol's case, a H atom is substituted to give a -OH functional group.

A summary of reactions that an alcohol and phenol undergoes:
As usual, please do not republish the image under your name, give credits.

Alkenes

The first topic i will be doing about is on Chemistry for H2 students. The current subject is being taught at JC levels but it may still help for secondary school students who are studying on Organic Compounds.

Alkenes are unsaturated organic compounds containing at least one carbon-carbon double bond (denoted: C=C). Alkenes have a general formula of CnH2n. Alkenes undergo electrophilic addition as well as oxidation reactions. The term electrophilic addition indicates the addition of an electrophile (a molecule which is attracted to electrons). C=C bonds contain one pi (π) and one sigma (σ) bond. The C in alkenes undergo sp2 hybridisation. Alkenes may also display cis-trans isomerism.

A summary of reactions undergone by alkenes: (click on image to enlarge, you can save it and print for yourself)
Choose the ideal one for viewing. I just happened to find that inverting the colours using paint produces interesting results. =)
P.S: Please do not edit and republish under your name.

Welcome

Welcome to Learnsg.blogspot.com. This blog is created in order to facilitate learning of all sorts. Hopefully to benefit local students here in Singapore. As an ex-student, i understand the hassle of flipping through textbooks or even lecture notes in order to find a particular information that slipped my mind. Hence, with this blog, i hope to colate mindmaps of various topics and subjects for convenience of anyone. The boundaries of the variety of subject is not confined to examinable subjects, i hope to be able to add information concerning other subjects as well. This may include foreign languages or other tips that is worth knowing. These posts will be categorised into topics on the sidebar for easier reference.