As you probably know from your extensive video gaming experience, while dynamite may be quite useful for explaining some of the basic science of how explosives work, it does not necessarily make a particularly good weapon, and it is much more suited to damaging buildings than people. For a more useful and ubiquitous explosive weapon, you need not look any farther than the trusty hand grenade.
The hand grenade is an explosive that, of course, fits in your hand, and one that you can easily throw to create a moderate-sized explosion. It doesn’t seem that different from dynamite, does it? It’s actually quite a bit different. First of all, as stable as dynamite is in comparison to pure nitroglycerin, it is not really stable enough to be worn on the belt of a combat soldier. The nitroglycerin inside the dynamite is simply too unstable for that kind of use. Instead, during World War I, the British created a hand grenade that used TNT as its primary explosive material.
TNT stands for trinitrotoluene and has a chemical formula of C₆H₂(NO₂)₃CH₃. You will notice right off the bat that those letters are quite similar to the ones found in nitroglycerin, C3H5N3O9, but in a slightly different order. In fact, the elemental components of TNT are nearly identical to those in nitroglycerin; however, the chemical bonds that hold TNT’s elements together are far stronger. As a result, TNT, though not quite as powerfully explosive as nitroglycerin, is far more stable. It is so stable that it can even be melted down into a liquid and poured into metal casings (a process that would not be recommended with nitroglycerin). This makes TNT the ideal explosive for hand grenades.
Aside from containing a more stable explosive, what makes a hand grenade different from a stick of dynamite? The main thing is the way its mechanical components function together to create a specific kind of explosion that make it optimal for a very specific set of purposes.
There are six main parts to a standard hand grenade: the body, the safety pin, the safety lever, the delay fuse, the detonator, and the charge. Before it is used, the pin of a hand grenade is fit into a hole on the spring mounted safety lever, keeping the lever in place. When you want to use the grenade, you must first hold tightly onto this lever and pull the pin. It’s important to hold onto the lever to keep the spring from popping it up before you are ready to throw the grenade.
When you do throw the grenade, this spring pops up the handle, and the detonation process is set in motion. The mechanical popping action of the lever ignites a delayed fuse inside a metal tube that travels down toward the center of the grenade. These fuses are specially made so that they take a precise amount of time to burn. Usually, this is about four seconds: just long enough for the grenade to reach its target. Once this fuse has burned all the way down to the bottom, it ignites a detonator, which is essentially a small explosive chemical that ignites as soon as the lit fuse touches it. The detonator sends out a shockwave throughout the grenade, which in turn causes the TNT charge to explode.
At this time, a chemical reaction happens inside the hand grenade that is very similar to nitroglycerin: once the chemical bonds of the TNT are broken apart, the oxidizing agent inside the chemical reacts with the carbon-based fuel inside the chemical to turn a small, cool volume of TNT into an extremely large and hot volume of gas.
What really makes a hand grenade a hand grenade, however, is not the explosion itself, but rather what the explosion does to the grenade casing. The earliest hand grenades looked like little metal pineapples for a very good reason, and it had nothing to do with SpongeBob. Each of the little sections of the pineapple-shaped piece of metal were separated by thinner pieces of metal, so that when the grenade exploded, the casing broke apart right along these gridlines. This made each little raised section of the grenade separate from the others and shoot out in every direction with the force of the explosion, thus turning this little metal ball into dozens of bullets flying in every direction at the same time. For the most part, it is the damage caused by these flying pieces of metal that is responsible for the destruction a grenade can cause, not the explosion itself. Explosions in a grenade, like the explosions inside of bullets, are meant primarily to push the little pieces of metal fast enough and far enough so that they go through people’s bodies and kill them.
In Fortnite, this is clearly not how the grenade delivers damage. If that were the case, any player within a wide range of the grenade would receive damage when it explodes, similar to what a player would receive from small-caliber bullets (like those shot from a submachine gun, for example). The explosive force damage, meanwhile, would be high, instantaneous, and similar to dynamite, though very much localized in the immediate vicinity of the explosion. While we do clearly see the Fortnite hand grenades dealing this kind of explosive damage, we don’t see any of the bullet-type damage indicative of flying shrapnel. From this, we can deduce that there is no shrapnel coming out of the grenades in Fortnite, and that they are meant simply as explosive devices used for their concussive force (which probably means that they are better suited to destroying structures and vehicles than eliminating other players).