Physics and War: Science of a Bullet (Part 1)

Science of a Bullet

Invention of chemical explosives has changed the nature of warfare and has led to numerous deaths and man-made devastation. The impact of this invention on the international politics and international relations need not be mentioned. The story of chemical explosives stretches back to invention of gunpowder by Chinese in mid 9th century. This enabled combat at a distance possible. The development of machine gun and other advanced weapons took the impact of war to another level. The technology is often preserved with great care with an intention to stay a step ahead of the enemy. This article deals with the working a bullet (in its basic form).

Bullets existed even before the invention of gunpowder though there are differences in the nomenclature. Invention of gun powder just accelerated the usage of bullets across the globe. Gun powder consists of charcoal, sulphur and potassium nitrate mixed in right proportions to achieve the explosive nature. A bullet consists of three major parts the core, region wrapping the explosive and a primer. The core of the bullet is the one that travels and hits the target. It is generally hardened metal and is generally round in shape. Primer acts like a link between the explosive and the pressure applied by the trigger. When a trigger is clicked, it causes the pressurisation of the primer region. The explosion caused at the primer spreads to the explosive and accelerates the bullet down the barrel.

The chemicals present in the gun powder when triggered generate large amounts of gas. The generation of the large amounts of gas need not always lead to explosion, but one should look at the time frame in which this process takes place. Imagine you make a small hole, very carefully, on a balloon. The balloon does not explode but rather it releases the gas slowly and gets flattened. The same is true with bursting of tyres which does not happen every time they are pierced. An explosion occurs only when large amounts of gas is produced in a very small time. The gas thus produced sharply rises the pressure. The risen pressure pushes the bullet down the barrel in the case of the gun powder explosion.

With the critical thinking skills picked up during our Phyiscs tuition classes, various questions should have surfaced in your minds. For example, why does the sudden rise of pressure does not cause an explosion to blast the gun itself? Isn’t bullet affected by gravity? Let’s discuss these questions in the next part of the article.