Chemistry Form 5: Chapter 5 - Making of Soap

Soaps are sodium or potassium salts of fatty acids. Soaps are prepared by hydrolyzing fats or oils under alkaline condition. This reaction is called saponification.

·         The fats or oils are hydrolysed first to form glycerol and fatty acids. The acids then react with an alkali to form the corresponding sodium or potassium salts.

·         The soap formed can be precipitated by adding sodium chloride. This is because sodium chloride lowers the solubility of soap in water.

·         The glycerol and excess sodium hydroxide solution are removed by rinsing the soap formed with water.

·         Soaps feel slippery and form lather when they are shaken with water.

Physics Form 4: Chapter 3 - Application of Bernoulli principle (WindSurfing)

 

• The air flow over the sail causes an increase in pressure on the windward side and a decrease on the leeward side
• Area of leeward side has a low pressure because of the high speed of the wind.
• A resultant force acts in the direction of F.
• This resultant force can be resolved into component to the right and left.
• The component to the right can be balanced by the surfer who pulls it to the left.
• Therefore, there exists a resultant force to the front so that the surfer moves to the front.
• Factors affect the resultant force is the strength of the wind and the shape of the sail. 

Mirror of Georgetown Heritage City

A cutting edge street art project by international artist Ernest Zacharevic, the project consists of six to 12 mural paintings created on the walls of buildings within the Georgetown heritage area. The paintings will depict figure drawings and portraits of various inhabitants of the city celebrating the multiculturalism and diversity of the town.

All photos above are courtesy of Ernest Zacharevic and Penang traveltips site

Ernest Zacharevic facebook page

 Penang Traveltips site

Physics Form 5: Chapter 3 - Application of Electromagnetic Induction (Torchlight)

Electromagnetic induction is the production of induced current by changing magnetic field. By using kinetic energy of shaking hand, electrical energy is produced to power the flash light through electromagnetic induction.

Kinetic energy ------> Electrical energy

• A powerful permanent magnet such as neodymium magnet is used because of small size with strong magnetic field. The permanent magnet is placed inside a plastic track which allow it to slide up and down.
• The shaking hands move the strong magnet to cut through the copper coils causing electromagnetic induction. 
• The electrical energy produced is stored in a capacitor that can be charged hundreds of thousands times.
• The bulb is an energy efficient ultra bright white LED that can produce a beam of light for several minutes after shaking the moving magnet for 30 seconds.

For more information, click below video

How She Passed the Driving Licence?

Physics Form 5: Chapter 3 - Application of Electromagnet (Telephone Earpiece)

When you listen to your telephone, the receiver in the earpiece reverses the electrical signals from the telephone wire back into sound that we can hear.

How does a telephone earpiece work?

Click on the diagram below to play!

No Malaysian in Harvard U.

KUALA LUMPUR, April 7 — Malaysians failed to gain admission into the world’s most prestigious university for the second year in a row due to a slide in the quality of applicants, said Harvard University’s selection panel chief for Malaysia.


Not only did no Malaysian student receive an offer letter but none apparently was even good enough to make it to the interview rounds. This comes after a controversy erupted over the quality of Malaysian education when Education Minister Tan Sri Muhyiddin Yassin pointed to a World Economic Forum report to claim that Malaysians had a higher standard of education compared to that in some advanced countries.


Datuk Dr Goh Cheng Teik, who leads the Harvard team that interviews prospective Malaysian students, said he was informed the quality of applicants had deteriorated.

“I called the Harvard College of Admissions Office and was told that although they received applications from Malaysian students, no one was shortlisted for interviews as they are not considered competitive enough,” he was quoted as saying by The Star.

A two-year absence from incoming Harvard freshman classes is enough to raise concerns over the quality trends of Malaysian education given that at least one Malaysian had been admitted to Harvard every year from 1985 to 2010.

A statement from Harvard’s interview panel showed that Malaysia was only fourth among Southeast Asian countries in terms of enrolment in the Ivy League institution.

Singapore has the highest number of Harvard undergraduates with 18, followed by Thailand with seven, Vietnam with six, Malaysia with five and Indonesia with two.

It was ranked the No. 1 university in the world last year by the Center for World-Class Universities of Shanghai Jiao Tong University. Some 34,950 applicants were received by Harvard for the 2016 graduating class and only 6.3 per cent were accepted.

Higher number of straight A+ scorers in SPM 2011

PUTRAJAYA: A total of 559 (0.12%) of 468,808 students scored straight A+ in last year's Sijil Pelajaran Malaysia (SPM) examinations, compared with 403 (0.08%) straight A+ scorers in 2010.

Education director-general Datuk Seri Abdul Ghafar Mahmud said overall student achievement in the examinations has continually improved in the past four years.

He said 506 of the straight A+ candidates were from national secondary schools and 53 from other schools, compared with 363 and 40 respectively in 2010.

"The overall SPM achievement for 2011 improved from the year before, with the National Average Grade at 5.04 compared with 5.19 in 2010," he added.

"The overall achievement of schools also improved, as the number of schools in the 'excellent' and 'good' categories increased by 13 and 60 schools respectively," he said when announcing the SPM 2011 results analysis at the Education Ministry here Wednesday.

Abdul Ghafar said schools were gauged using the School Average Grade and categorised as "excellent", "good", "satisfactory", and "potential".

Physics Form 5: Chapter 1 - Application of Reflection of Sound

Echoes are caused by the reflection of sound. A sound wave will continue to bounce around or reverberate until it has lost all its energy. A wave has some of its energy absorbed by the objects it hits. The rest lost as heat energy.

The phenomenon of the reflection of sound is used to determine the distance between the two objects, for example depth of seabed, depth of cave or width of a valley. The type of sound used must be ultrasound.

Sonar (Sound Navigation and Ranging). Sonar is used to detect underwater objects (corals / fishes) or to determine the depth of the water by means of an echo. Sonar equipment emits a high frequency sound signal which is reflected by the object in the water. The reflected sound wave is received by the sonar receiver. The time taken for the echo to return is used to determine the distance of the object below the water surface. 

Sonar waves of high frequency is used because it possesses more energy, high penetration power and can travel further through water.

Click on the diagram below to play!

Physics Form 4: Chapter 5 - Ray Diagrams of Convex Lens

Ray Diagram Rules for Convex Lens

1. Any incident ray travelling parallel to the principal axis of a convex lens will refract through the lens and travel through the focal point on the opposite side of the lens.
2. Any incident ray travelling through the focal point on the way to the lens will refract through the lens and travel parallel to the principal axis.
3. Any incident ray passes through the center of the lens will in affect continue in the same direction that it had when it entered the lens.

Examples of ray diagram with different object distance

Penang Tops STPM Result

PENANG schools have performed better in the STPM examinations last year with the passing rate for students scoring between one principal and five principals at 97.02% compared to the national average of 93.96%.

State Education Department deputy director Dr Sharifah Bee Aboo Bakar said the joint effort of the teachers had contributed to the academic achievements of the students last year.

She said that in 2010, a total of 2,494 students sat for the exams where 96.67% of them scored between one principal and five principals and it was 2,409 students in 2009 with 96.75% obtaining between one and five principals.

“A total of 3,062 students sat for the exam last year and 2,523 students were from the government schools with another 345 from private schools and 194 were private candidates,’’ she said at a press conference held at SMJK Jit Sin in Sungai Rambai near Bukit Mertajam yesterday.

Chemistry Form 4: Chapter 2 - Bohr's Atomic Model

Neils Bohr was born on October 7, 1885 in Copenhagen, Denmark. In 1922 he won the Nobel  prize for physics. Bohr was a professor at the unoversity of Copenhagen. Neils Bohr produced a theory about the structure of an atom based on Rutheford's Plum Pudding model. Bohr discovered that the electrons travel in orbits. Outer orbits could hold more electrons than the inner orbits. He suggested that when an electron jumps from an outer orbit to an inner orbit it emits light which called photon.

This model was created by Neils Bohr in 1915. In the center is the nucleus which is composed of protons and neutrons. It is orbited by electrons. The nucleus is about 100,000 times smaller than the radius of the atom.

STPM Result Next Wednesday

KUALA LUMPUR: The result of last year's Sijil Tinggi Persekolahan Malaysia (STPM) examination will be announced on Wednesday, the Malaysian Examinations Council said.

In a statement, it said candidates would be able to obtain their results at their respective schools from 12 noon while private candidates would obtain theirs through the post.

Candidates can also check the result via the text message by sending STPM ResultIC number to 15888 or at the council's website at http://www.mpm.edu.my from noon on that day.

A total 50,602 candidates sat for the examination last year comprising 46,817 candidates from government schools, 1,266 from private schools and 2,519 private candidates. - Bernama

Busy With 5S at School

5S is the name of workplace organization methodology that uses a list of 5 Japanese words which are seiri, seiton, seiso, seiketsu and shitsuke.

For the past one month, I had been busy with 5S implementation in my school. I have been given a task to become Person In Charged for three places in my school compound. No doubt, it affects my teaching ability at class. Besides 5S, I still need to carry out other responsibilities such as adviser for badminton and chess's club, form teacher job, head of science department, disciplinary work, school magazine, keying student's biodata  and checking stock items. Nearly forgotten, I have to prepare questions for Peperiksaan Penggal 1 examination this week!

 

Do not get me wrong! I am not lamenting about my jobs. In fact, 5S brings more benefits to my workplace.

The Benefits of 5S

• Greater efficiency in achieving goals
• Greater readiness for new tasks
• Fewer hazards
• Less spending on replacing lost or damaged items
• Less stress
• Greater self-esteem
• More space

What I need to do is persevere. This is just a temporary set back to my teaching ability at class. I pray to God for his guidance and peace to go through this period. I give thanks to God for training me at this moment so that I am able to be a better leader in future. God wants me to be a HEAD and not a TAIL. So far, I have executed my responsibilities well. Glory be to God.

Thank you to my students for helping me doing 5S

Physics Form 5: Chapter 1 - Loudness of Sound

2. Loudness - Amplitude

The loudness of a sound depends on the wave's amplitude.
The louder the sound, the higher the amplitude. So, amplitude is also a way of measuring the energy has.


The higher the energy, the higher the amplitude resulting a louder sound.


The system used to measure the loudness of sounds is the decibel system, given the unit dB.

Range (dB)	Description	Examples
0 - 30	Very Quiet	This is the threshold of human hearing, up to the sound of a quiet whisper.
31 - 50	Quiet	This is an average quiet house, with maybe the sound of a fridge running or someone moving around.
51 - 70	Normal	Regular daily sounds like people talking.
71 - 90	Loud	This is the point where a sound becomes annoying or distracting. Vacuums or a noisy car on a busy street are at these levels.
91 - 110	Very Loud	Most people will try to avoid being in areas this loud. Prolonged exposure can cause permanent ear damage. Temporary effects, like "stereo hiss", may happen.
111 +	Painful!!!	Even limited exposure to levels this high will cause permanent hearing loss.

Amplifier is a device to increase the loudness of sound by use of an external energy source. It drives the loudspeakers used in PA system to make the human voice louder.

Physics Form 5: Chapter 1 - Pitch of the Sound

Generally, there are three characteristics of sound:

• frequency affects pitch of the sound
• amplitude affects loudness of the sound
• wave form affects quality of the sound

1. Frequency - Pitch

The frequency of a wave is measured as the number of complete vibrations of particles of a medium per unit time. A commonly used unit for frequency is Hertz.

Pitch is an auditory sensation in which listener assigns musical tones to relative positions on a musical scale based on the frequency of sound. A high pitch sound corresponds to a high frequency sound wave and low pitch sound corresponds to a low frequency sound wave.

Changing Pitch:

Click on the diagram below to play!

A string vibrates with a particular fundamental frequency. It is possible, however, to produce pitches with different frequencies from the same string. The four properties of the string that affect its frequency are length, diameter, tension, and density. These properties are described below:

1. When the length of a string is changed, it will vibrate with a different frequency. Shorter strings have higher frequency and therefore higher pitch. 
2. Diameter is the thickness of the string. Thick strings with large diameters vibrate slower and have lower frequencies than thin ones. 
3. Tightening the string gives it a higher frequency while loosening it lowers the frequency. 
4. The density of a string will also affect its frequency. Remember that dense molecules vibrate at slower speeds. The more dense the string is, the slower it will vibrate, and the lower its frequency will be. Instruments often have strings made of different materials. The strings used for low pitches will be made of a more dense material than the strings used for high pitches.

Name	Frequency Range (Hz)	Characteristics
Infrasonic	0 - 20	Very low frequencies of sound that the human ear can’t detect, but you mayfeel the rumbling of the waves through your body.
Sonic (AKA Audio)	20 - 20 000	Normal range for human ears, although not everyone (especially the elderly) will hear to the extremes of this range.
Ultrasonic	20 000 +	Beyond normal hearing for humans, although some animals (like dogs) hear part ways into this range. Also used in medicine (e.g. ultrasounds for pregnant women).

Can you sing this high-pitched song?

Rest In Peace Whitney Houston

This page is dedicated to you on my lesson about the pitch of the sound. God really loves you and gives you the gift of high-pitched sound. Thanks for your song!

Congrats to Kah Hooi

For the blind: Freedom teammates, Kah Hooi (right) and Bong Zheng Liang showing their safety cane which won them second prize for the Solar Energy Application Design category

I had taught Kah Hooi from Form 1 to Form 5. He was my former student of Physics, Chemistry and Add Maths. He scored 'A' in all the three subjects. I attribute his SPM success for his right attitude towards study. Today, I feel proud of him after learning that he won the first runner up prize for Solar Energy competition held at Heng Eee High School. Well Done! May God continue to bless you abundantly!

Extracted from The Star newspaper:

The Energy Saving Awards 2012 also saw another competition category — the Solar Energy Application Design Compe-tition. The first and second runners up went to teams Freedom and Solar Junior, both from Heng Ee High School.Tan Kah Hooi, 19, from team Freedom, said that they built a cane for the blind with safety features.

“The cane has in-built LED lights and an alarm,” he said.

“This is to help the blind to attract more attention if they are harmed or attacked,” he said.

You Put Me in Shame, Thank You

Nicholas Vujicic came into the world in 1982 in Brisbane with neither arms nor legs. His parents were devastated when they saw their first born new baby for the first time. They worried about their son how he could make his way through life with such a massive disability.


Imagine being born without arms and legs, how he could live a normal happy life. He just no ability to dance, to run, to hold, to feel with his fingertips or even to hug his loved ones. What a tragic!

Throughout his childhood, he constantly questioned why he was different than all the other kids surrounding him; why he was the one born without legs and arms. He struggled with loneliness and depression.

He wondered what the purpose behind his life was. He then started to realize how God loved him so much in the past and gave him a vision to be a motivational speaker to encourage multitude of people in a religious and moving way. Nick said, " I found the purpose of my existence and also the purpose of my circumstance".

He has since traveled around the world speaking to millions of people, giving them inspiration, courage, and the hope he’s always dreamed of. “If God can use a man without arms and legs to be His hands and feet, then He will certainly use any willing heart!”


A visitor at a school for the disabled was writing questions on the board for the children. Soon he wrote this sentence: " Why has God made me able to walk, hear and speak and made you disabled?" The shocking sentence hit the children like a cruel slap on the face. They sat paralyzed, pondering the dreadful word "Why?" And then a little girl arose.

With her lip trembling and her eyes swimming with tears, she walked straight to the board. Picking up the chalk, she wrote with a steady hand while limbing these precious words:

"Yes, God Father, for this was your good pleasure"

What a reply!

Chemistry Form 5: Chapter 1 - Effect of Concentration on Rate of Reaction

Experiment to show the effect of concentration on reaction rate

Sodium thiosulphate solution react with dilute sulphuric acid to form a yellow precipitate of sulphur. In this experiment, the time taken for the formation of sulphur to cover the mark 'X' until it disappears from sight can be used to measure rate of reaction.

As the concentration of sulphuric acid is increased, the rate of reaction between sulphuric acid and sodium thiosulphate increases.

Explanation using collision theory

·      When the concentration of the solution of a reactant increases, the number of particles per unit volume of the solution also increases.

·      With more particles per unit volume of the solution of the reactant, the frequency of collision increases.

·      This causes the frequency of effective collision to increase. Hence, the rate of reaction increases.

Physics Form 4: Chapter 1 - Micrometer Screw Gauge

Ratchet exerts correct amount of pressure on the object to be measured. 

How to take reading from micrometer screw gauge?

Click on the diagram below to play!