When we think of explosives, we usually think of a round spherical object with a black shell and a lead.
However, have you heard of "liquid explosives"?
To test the power of liquid explosives, scientists put them in bottles and threw them on a stack of steel plates. As the bottle split apart, only a puddle of residual liquid remained on the steel plate.
The next step is to remotely control the hammer to smash into the puddle of liquid through a device as shown in the picture.
In the face of the menacing hammer, the seemingly lethal liquid burst out with tremendous force, not only overturning the hammer, but even sending the steel plate flying into the air. Why is "liquid explosive" so powerful?
The essence of "liquid explosives".
The scientific name of "liquid explosive" is nitroglycerin, which has a light yellow viscous liquid appearance. It is an organic compound that contains three nitro groups and is one of the most common explosives.
Compounds containing nitro are notoriously "temperate", and in addition to nitroglycerin, Tai Case and Octogen are all excellent explosives, which are common ingredients in the detonation formulations of detonators, atomic bombs, and even nuclear weapons.
Having said that, the reason why nitroglycerin can become a "liquid explosive" is mainly related to its chemical reaction. Nitroglycerin is extremely unstable in nature and can undergo a chemical reaction to decompose into carbon dioxide, water vapor, nitrogen and oxygen when heated, rubbed or impacted.
It is not these substances that are scary, but according to the law of conservation of energy, a substance with high energy is decomposed into a matter of low energy, and the energy difference in it will inevitably be converted into heat energy, and eventually too much heat energy exceeds the limit of the air to bear, and the phenomenon of explosion is formed.
Past lives of nitroglycerin
Although we now understand how nitroglycerin exploded and even apply it to clinical medicine, in the time when it was first discovered, it caused so many casualties that its researchers were given the title of "death dealer".
This man is known as Alfred Nobel.
The first to discover the special properties of nitroglycerin was the Italian chemist Sobrero, who in 1847 reported that "this liquid can explode by vibration, and what it will be used for in the future can only be told by future experiments." This phenomenon aroused the great interest of the young Nobel, whose first goal was to find a way to safely detonate nitroglycerin.
In 1862, with an earth-shattering bang, Nobel's experiment succeeded. Prior to that, there were only records of its explosion with "heating or gravity shock", and this time he achieved the same effect with a small amount of ordinary gunpowder.
For this, the Swedish Society of Science awarded him a gold medal for making nitroglycerin an industrial explosive for the first time. And the detonation of nitroglycerin with ordinary gunpowder also became the predecessor of the "detonator".
This achievement undoubtedly encouraged Nobel's determination. However, just two years later, the "loud noise" that brought him glory took the lives of his brother and four other experimenters, and his father was seriously injured in the explosion.
But instead of giving up on the experiment, he learned from the pain, summed up the reasons for the many failures, and finally found that he could use cold water pipes to disperse the heat of the nitroglycerin reaction to avoid causing an explosion in the production process. The birth of the "cooling method" made nitroglycerin available for large-scale production.
Because nitroglycerin has a strong explosive force, it can greatly save manpower in various blasting projects, and it will be popularized soon after it is put into production. Later, he continued to improve the application of nitroglycerin, invented a solid explosive mixed with diatomaceous earth, and added nitroglycerin to celluloid formulations to make mixed smokeless explosives. He himself became famous, becoming a millionaire with patent rights.
Thanks to Nobel's efforts, nitroglycerin became a weapon of war, but at the end of his life, it appeared in another form, that is, as a drug to dilate blood vessels, "blowing" up the veins of his blood transfusion blockage.
Perhaps it was this dramatic life that made him feel a lot of emotion, and a year before his death, he announced in his will that he would use part of his life income as a fund to establish the Nobel Foundation, and the interest of the fund would be used as a prize to be awarded to people who have made outstanding contributions to all aspects of science - this is the world-famous Nobel Prize.
The present life of nitroglycerin
Today, thanks to the tireless efforts of generations of scientists, nitroglycerin has shown its extraordinary potential in many more fields. It is no longer just the embodiment of war, but even a cure for life.
In the field of national defense science and technology, TNT, an explosive made of nitroglycerin and toluene, was known as the "king of explosives" until the end of World War II because of its excellent blasting performance and stability. In addition, nitroglycerin explosions are also widely used in liquid-fueled rockets and rocket engines because of the huge energy that can provide enough thrust for rocket starting.
In the field of medicine, nitroglycerin is an important cardiovascular drug that can treat diseases such as angina pectoris, heart failure, etc. Nitroglycerin, which is used as a drug, is a dilution of "nitroglycerin in explosives", but its chemical formula is the same, but it still has a certain instability.
It can "explode" in the blood vessels, dilate the peripheral arteries and veins, thereby lowering blood pressure, reducing the resistance of the heart to pump, reducing the heart's oxygen consumption, and relieving the symptoms of angina.
In the industrial field, nitroglycerin can be used as a raw material for plastics, dyes, solvents, synthetic fibers, etc., and is also one of the important materials for metal surface treatment and wood insect control.
Weapons for terrorists
As mentioned above, it is up to humans to decide how to use the enormous energy contained in nitroglycerin. It can be used for medical purposes or as a catalyst for violence. In the eyes of some criminals, the nature of nitroglycerin just means "concealment" and "strong lethality".
In 2016, at Heathrow International Airport in London, London, the London police arrested a group of suspects for carrying "Coke". A bottle of Coke will not be considered a dangerous item at any security checkpoint.
But at the bottom of this particular bottle of Coke, an additional fake base is installed, which is filled with this liquid explosive and dyed the same color as Coke to get away with it. In addition, they prepared batteries, wires, and capacitors in order to assemble them into detonators that could act as detonators.
Because the two liquids in the bottle are inherently harmless, it is easy to evade detection by security instruments. If the terrorists were not apprehended in time, when they got on the plane, they would take the props into the toilet to quickly assemble them, and then detonate the liquid explosives, which are powerful enough to destroy the fuselage of the plane, potentially causing thousands of casualties.
Fortunately, the intelligence officers of the British police had already received the news and monitored the terrorists for several months, otherwise this terrorist attack would have been the second "9/11" incident.
Methods for the detection of hazardous liquids
As a result of this incident, various transportation hubs have strengthened their testing regimes for liquids. Nowadays, when we go through security, we usually need to use a machine to detect liquids, or "take a sip", but airports are strictly forbidden to carry all liquids.
At present, the liquid security detector used in the security inspection office can basically detect all kinds of flammable and explosive liquids, and the principles of its detection are X-ray scattering imaging technology and magnetic nuclear resonance imaging technology.
X-ray scattering imaging techniques:
The principle of this technique is that the scattering probability of X-rays encountering different substances is different, and the scattering probability is proportional to the electron density of the detected item, which in turn is proportional to the mass density, so the scattering signal increases with the increase of mass density.
The security detector can receive the scattered signal to determine the mass density of the liquid, because flammable and explosive liquids usually have a large mass density, so they can be distinguished from drinking water;
MJMRI:
The principle of this technology is that the security scanner disrupts the arrangement of the atomic nuclei inside the liquid by emitting low-frequency radio waves into the liquid. When they are rearranged, they emit signals, which are quickly analyzed by the system's computer.
Because the signals of different compounds are different, flammable and explosive liquids can be quickly distinguished.
With these screening technologies, we can keep the risk of these "dangerous goods" within a safe range and turn them into unlimited potential for the benefit of human life.
Nitroglycerin, as a "liquid explosive", is finally no longer as alarmist as recorded in history. It can be seen that these substances from nature contain infinite possibilities, and human beings should be in awe of nature and use nature for their own use.
Bibliography:
[1] Deng Zhenping.Development status of security inspection technology for liquid dangerous goods[J].Value Engineering.2012(29):195-196;
[2] Wang Tongzhen.Analysis of the hazards of liquid bombs and their detection technology and instruments[J].Police Equipment.2010(9):67-69
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