Physics Form 5: Chapter 5 - Nuclear Chain Reaction

• If neutrons from the fission of uranium-235 continue to split other nuclei causing further fission, a chain reaction has occurred.
• A chain reaction refers to a process in which neutrons released in fission produce an additional fission in at least one further nucleus. This nucleus in turn produces neutrons, and the process repeats.
• The process may be controlled (nuclear power) or uncontrolled (nuclear weapons).
• In order for a chain reaction to take place, a minimum of one neutron from each fission must trigger further fission.
• At the same time, the mass of fission material must exceed a certain minimal mass known as the critical mass.
• A critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties (e.g. the nuclear fission cross-section), its density, its shape, its enrichment, its purity, its temperature and its surroundings.
• If the material is less than this critical mass, too many neutrons escape without hitting any nuclei thus preventing a chain reaction from happening.
  

Click on the diagram below to play!

Good Samaritan Lacks in China

  What do you feel after watching this footage?

China has improved tremendously for the past two decades in terms of economic, military, space exploration, sports, super infrastructures, magnificent skyscrapers, and so on. Despite of these achievements, China is experiencing a drop in moral values among its citizen. I am saddened that China now lacks of good Samaritan. What is so proud about being a superpower nation when its people lacks of showing love to others? Buck up China, rule the world with love. 

I pray that God's love will sweep across the China and brings revival to its people. God loves China.

Animals are better than human. I hope I am wrong.

Race Quotas, Politics Led to Falling UM Standards

KUALA LUMPUR, Oct 17 — A World Bank publication has found that standards at Universiti Malaya have fallen and the institution has been kept at a disadvantage because of race-based admission quotas and political interference in university management. In contrast, Singapore’s decision to prioritise research, keeping English as the medium of instruction and a merit-based admissions policy have all contributed to the success of the National University of Singapore’s success, according to “The Road to Academic Excellence,” which studies what contributes to a world-class research university.

The study also noted that Malaysian secondary school students are not well prepared for tertiary education.
It points out that the Malaysian education system promotes rote learning, conformity and uniformity rather than fresh and creative thinking. The study is led by two scholars — Philip Altbach and Jamil Salmi — while various chapters see contributions from various academics.

According to the study, “at an early stage, the Singapore government realised the universities’ role in sustaining economic growth. “In contrast, after 1970, UM’s institutional goals reflected the New Economic Policy, an affirmative action plan for ethnic Malays and indigenous groups, put in place in the wake of disastrous 1969 ethnic riots that took the lives of hundreds of people on both sides of the racial divide.,” the study found. The authors said that apart from the student quota system, the NEP translated into more scholarships to Bumiputeras, special programmes to facilitate their entry into higher education institutions, and the use of the Malay language in place of English in the entire education system by 1983.

“In UM and in government, the policy impact spiralled upward so that Bumiputera staff members, over time, secured almost all senior management, administrative, and academic positions. “As NUS kept pace with the demands of a growing economy that sought to become competitive internationally, with English continuing as the language of instruction and research, UM began to focus inward as proficiency in English declined in favour of the national language — Bahasa Malaysia — and the New Economic Policy’s social goals took precedence.”

Physics Form 4: Chapter 5 - Introduction to Curved Mirror

Concave Mirror

Convex Mirror

• Principal axis is the line through the centre of curvature and the pole of the mirror.
• Pole is the point where principal axis meets with mirror surface.
• Centre of curvature is the centre of sphere that the mirror forms part.
• Radius of curvature (r) is the radius of sphere.
• Principal focus is the point to which all rays parallel to the principal axis converge or from which they appear diverge.
• Focal length (f) is the distance between the pole and the principal focus.

• Parallel reflected rays converge at focal point.
• Real focus since the reflected rays actually pass through it.

• Parallel reflected rays appear to diverge from focal point.
• Virtual focus since the reflected rays do not pass through it.

Can You Read This......

Good example of a Brain Study

If you can read this you have a strong mind:

 

7H15 M3554G3 53RV35 7O PR0V3 H0W 0UR M1ND5 C4N D0 4M4Z1NG 7H1NG5! 1MPR3551V3 7H1NG5! 1N 7H3 B3G1NN1NG 17 WA5 H4RD BU7 N0W, 0N 7H15 LIN3 Y0UR M1ND 1S R34D1NG 17 4U70M471C4LLY W17H 0U7 3V3N 7H1NK1NG 4B0U7 17, B3 PROUD! 0NLY C3R741N P30PL3 C4N R3AD 7H15.

 

Chemistry Form 4: Chapter 9 - Haber Process

1. The physical properties of ammonia are:
• Colourless and alkaline gas
• Strong pungent smell
• Highly soluble in water

2. Ammonia usually produces white fumes of ammonium chloride when reacted with hydrogen chloride.

3. The main uses of ammonia are:
• Manufacturing nitrogen fertilizers
• Manufacturing nitric acid through Ostwald process.
• To make explosives, dyes, household cleaners and nylon
• As a cooling agent.

Making of Ammonia

Ammonia is manufactured by combining nitrogen and hydrogen in an important industrial process called the Haber process. The reaction is reversible and the production of ammonia is exothermic.

• Nitrogen gas is obtained from the fractional distillation of liquid air.
• Hydrogen gas is obtained through the reaction between natural gas and steam.
• Nitrogen and hydrogen are mixed in the ratio of 1 : 3

Click on the diagram below to play!

How to separate ammonia

When the gases leave the reactor they are hot and at a very high pressure. Ammonia is easily liquefied under pressure as long as it isn't too hot, and so the temperature of the mixture is lowered enough for the ammonia to turn to a liquid. The nitrogen and hydrogen remain as gases even under these high pressures, and can be recycled.

 An ammonia production plant. Photo courtesy of WMC Resources Ltd

 

Chemistry Form 5: Chapter 4 - Exothermic and Endothermic Reaction

Chemical energy is needed to transform a chemical substance into a new product through chemical reaction. Therefore, breaking or formation of chemical bond involves energy, which may be either absorbed or released from a chemical reaction.

• To break the chemical bond, energy from surrounding is absorbed resulting decrease of temperature of surrounding.
• To form the chemical bond, energy from reaction is released to the surrounding resulting increase of temperature of surrounding.

 

Exothermic Reaction	Endothermic Reaction
Chemical reaction that gives out heat to the surroundings.	Chemical reaction that absorbs heat from the surroundings.
Temperature of the surroundings increases.	Temperature of the surroundings decreases.
The total energy of reactants is more than total the energy of products.	The total energy of reactants is less than the total energy of products.
Bond formation releases more energy than is required in the bond breaking.	Bond breaking requires more energy than the energy that is released during bond formation
Examples: Combustion of fuel, burning of metal, neutralization, respiration, rusting of iron, reaction of a reactive metal with acid, reaction of alkaline metals with water, Haber process, freezing, condensation, dissolving alkali or concentrated acid in water, dissolving anhydrous salts in water.	Examples: Thermal decomposition of nitrate or carbonate salts, reaction of acid with hydrogen carbonate, photosynthesis, melting, boiling, sublimation, dissolving ammonium or potassium salts in water, heating of hydrated salt.

Click on the diagram below to play!

iMac, iTunes, iPod, iPhone, iPad, iCloud ......but iMan is GONE

He was so awesome, handsome, genius, wealthy, creative, innovative, talented salesman and gifted entrepreneur. He was almost near perfect in every aspects in human eyes. I thanks God for his wonderful creature named STEVE JOBS. With his foresight, he invented something that we don't even know that we really needed. He was a great trendsetter, started numerous fashion products that others copy.

But, he has gone.................................

He was 56 years old before he took his last breath. It was too sudden for the world to accept his death news. His fighting spirit against all odds should be remembered. The moment he knew his life is going to end soon, he totally changed. Without wasting time, he determined himself to do something in a more meaningful way in his life. His words describe all his thoughts about life ....

Being the richest man in the cemetery doesn’t matter to me … Going to bed at night saying we’ve done something wonderful… that’s what matters to me.”

 “We don’t get a chance to do that many things, and every one should be really excellent. Because this is our life. Life is brief, and then you die, you know? And we’ve all chosen to do this with our lives. So it better be damn good. It better be worth it.”

“Almost everything–all external expectations, all pride, all fear of embarrassment or failure–these things just fall away in the face of death, leaving only what is truly important. Remembering that you are going to die is the best way I know to avoid the trap of thinking you have something to lose. You are already naked. There is no reason not to follow your heart.”

Not only that, he loves his loved ones................

This above picture I like the most one and taken after Steve Jobs icloud's presentation. It tells you something ...........that I can't describe it with words.

Life is really very brief. From the young Steve Jobs to the bedridden patient. Nobody can escape death. Steve Jobs has all the resources to heal his long-fighting pancreatic cancer. He has money, he has the best doctor, he has the best medical facilities but still can't run away from death. One day, we all sooner or later will also going to face death as Steve Jobs encountered. But, he had proved that he did something wonderful to the world before he passed away. Not many people able to do it. There are still many people live with no purpose in their life. So pathetic ...! We should all emulate Steve Jobs fighting spirit for his clear goal.

Anyway, I still have this thought that play in my mind. A thoughts that many people ignored it or pretended that it is not exists. For me, this is very important spiritually thoughts.

What happen to me after I died?

Do you have answer ...........................