For the aspiring forensic scientists...

We have learnt from all the police/detective shows that we see so much of on television that fingerprints are important evidence to collect from the crime scene. Fingerprints are left behind on everything that we touch due to the sweat on the skin as well as the oil, dirts and salts that are lodged in the tiny ridges of our fingertips. One of the simplest methods to get samples of fingerprints is to dust the touched area with magnesium powder, then "lift" the prints by photographing them.

Up to now, fingerprints can only be obtained from smooth and hard surfaces such as plastic and glass. Recently, forensic experts from the University of Abertay Dundee and the Scottish Police Services Authority (SPSA) have developed a method of getting fingerprints from cloth. This is accomplished using a technique called vacuum metal deposition. The cloth is first placed in a vacuum and then coated with a layer of gold. Zinc is then introduced and it will adhere to gold at places which have not experienced any contact by human hands. In this way, the scientists will be able to see the fingerprints as areas that are not covered by the grey film of zinc.

While it is still difficult to obtain clear enough fingerprints from fabrics for identification purposes, this technique provides evidence that can help the police to deduce the order of events that occurred at the crime scene. For example, they can now find out whether a person has been pushed down a building from the back by looking for handprints on the back of the shirt that he/she was wearing when it happened. New materials for CSI~

Carcinogenic Benzene

In the lecture this morning, it was mentioned that benzene is a carcinogenic compound, which causes people who are exposed to it for long periods of time to develop cancer. The carcinogenic property of benzene was only conclusively recognised a few decades ago. I remember one of my lecturers in university telling us that chemists of the past used to use benzene to wash their hands after handling organic experiments.

Here is quite an old video about how a worker developed leukaemia after being exposed to benzene on his job.

Help!!! I don't understand hybridization!

I know that some people will panic every time we talk about hybridization. It is one of those things that, at this stage, you need to just take for granted and not question too much, because you are not taught quite enough to comprehend the theory fully.

Here are some videos that may help you to visualise what hybridisation is about and hopefully, you will be able to understand it better.

This video was shown during the lecture

This video is rather clear in explaining how sp3 hybridisation occurs. A little long-winded at the beginning but have patience and watch it to the end as the second half of the video is good.

And here is the video for sp2 hybridisation. Similarly, watch it to the end!

World's Smallest Periodic Table

A Chemistry Professor at the University of Nottingham in U.K. received a super cool (in the most geeky way) present for his birthday -- the Periodic Table etched on a strand of his own hair. This was done for Professor Martyn Poliakoff by the nanotechnlogists of the university. This is what it looks like:

The 118 elements of the Periodic were carved using a beam of gallium ions. This technique is usually utilised to do repair works on extremely small components of semi-conductors. So, how small is this Periodic Table? Each letter carved has a height of four microns -- that is 4 × 10^-6 m. The entire Periodic Table is 88 microns wide, and 46 microns tall. If this were to be done on a Post-it note, almost one million of them can be fitted on a single piece of the note paper. 


A video was made to show how the process was carried out. Check it out here:

Counterfeit eggs in China

If you have read the Straits Times a few days ago, you would have seen a report on how some people in China are using chemicals to make counterfeit eggs. These fake eggs look exactly like the real ones and the total cost of making each of them is only one-tenth the price of a real egg. These are the steps to make a fake egg:

information from http://www.weirdasianews.com/2007/05/04/chinas-10-steps-to-make-a-fake-egg/

And a video to show the actual process:

The process used to create the spherical yolk and egg white is actually a technique commonly used in molecular gastronomy to make little spheres which are liquid in the centre, and have a thin jelly layer outside.  I have tried this item of molecular gastronomy, and saw the chefs making the spheres with mango juice. What the chefs do is to dissolve some sodium alginate (or what is known as sodium alga acid in the flowchart given above) in fruit juice, then drip drops of the mixture into a solution of calcium ions. The calcium ions will react with the alginate to form a thin membrane, enveloping the fruit juice in it and forming a small ball. This is the exact reaction the counterfeiter in the video carried out when he was swirling the orange sphere around in the colourless liquid in the mould. While chemicals such as sodium alginate and calcium chloride are not harmful to the human body, I can't say the same about some of the rest of the chemicals the counterfeiters use to make the eggs.

Fritz Haber -- great or evil?

These two weeks, we have been studying about systems known as chemical equilibria. One of the most important chemical equilibrium reactions in the world is the Haber Process, which is the reaction between nitrogen and hydrogen gas, to form ammonia: N2 + H2 --> NH3.

This is an important process as it produces ammonia, which is an important starting material for the production of fertilizers. With the Haber Process, the world is no longer reliant on natural deposits for nitrogen-containing compounds. Nitrogen, which is the main component of air, can now be harnessed to produce the nitrates and nitrites required to manufacture fertilizers. At the present, 100 million tons of nitrogen fertilizer is being produced yearly through this process and this amount of fertilizer is responsible for feeding one third of the world's population.

So who was the chemist behind this amazing innovation that changed how the world feeds? He is a German chemist, named Fritz Haber. When he was at the University of Karlsruhe from 1894 to 1911, he worked with another chemist, Carl Borsch to develop the Haber Process. In 1918, both scientists won the Nobel Prize in Chemistry for their innovation.

While the Haber Process aided humanity by enabling mankind to produce fertilizers easily, leading to an increase in food production, the ammonia produced is also highly sought after for the production of explosives. With this technology, Germany was able to easily produce the ammunition required for the first World War, which extended their path to surrender, and prolonged the suffering of the parties involved in the war.

On top of contributing to WWI by providing his country with the means to produce explosives, Fritz Haber also played a major role in developing chemical warfare for the war. He developed chlorine gas to be used to poison the opponent forces and was even present at the war zone to release the gases on the soldiers. When exposed to chlorine gas at a high concentration, the gas will react with the water in one's lungs to form hydrochloric acid. This will cause the sacs in the lungs to break down, causing the lungs to be flooded. In other words, one is drowned internally by the moisture present in one's lungs.

Fritz Haber was proud of his contributions as a chemist to the war, but his wife, who was also a chemist, opposed his work on poison gas. She committed suicide on the day Haber left to oversee the release of poison gas on the Russian to demonstrate her stand.

Despite Haber's contributions to Germany during the first World War, he had to leave Germany in 1933 as he was Jewish. He moved to England and finally passed away due to heart failure in the Middle East.

The Haber Process helped to save the world from wide-spread hunger, but at the same time, provided man with the avenue to produce explosives easily. Such is an example of how Science can sometimes be a double-edged sword.

The Science in Inception

I formally declare: Inception is now my new favourite movie. I love the whole concept of intruding dreams, bending reality and manipulating situations. Here is an article from New Scientist that discusses some of the neuroscientific concepts on which the movie is based.

If you haven't watched the movie, go watch it over the weekend if you have finished studying for your Lecture Test!