In the latest flare-up of Middle East violence, Israeli troops shelled a refugee camp in Gaza in response to a Palestinian mortar attack. The shrapnel killed a Palestinian baby. Israeli troops also captured a boatload of arms bound for Gaza that included rockets, guided missiles, and rocket-propelled grenades. What are these various weapons, and how deadly are they?
Mortars were invented around 1500 as siege weapons to break down castle walls. They're tubes of metal that generally range from 3 to 5 feet in length and weigh 20 to several hundred pounds. They are set on the ground and aimed into the air. Mortar shells are dropped into the tube. The shells, depending on the diameter of the mortar, range from the size of a soft-drink can to that of a coffee can. A propulsive charge sends the shell into the air.
A mortar shell can be launched thousands of feet, which makes it an indirect fire weapon. That means the people launching the weapon cannot see their target, or it means that the weapon fires at a high trajectory. A small mortar can be operated by two people: one to drop the shells, the other to set them off. Under the Oslo peace accords, mortars are banned from Palestinian territory. Although the shells launched by the Palestinians were of low quality and caused little damage, a small high-quality shell is the equivalent of a stick of dynamite and can blow up a car. Larger shells are several sticks' worth and can destroy a house.
Shell is a generic term for many different types of projectiles. Mortar shells, for example, are metal casings filled with an explosive charge. When the Israelis respond to mortars by "shelling" Palestinians, that generally means they are shooting large-caliber guns that are mounted on armored combat vehicles, of which tanks are a subset. (Caliber refers to the diameter of the bore of a gun.) Shrapnel has come to refer to the pieces of flying metal from a shell casing.
Rockets are more sophisticated devices than mortars. Rockets are self-propelled, which gives them greater range than mortars. After launch, a rocket's combustion products keep propelling it after it has left the tube. A small rocket can go a couple of miles, and a large one can travel 20 miles. The damage done by a single small rocket is equivalent to the damage done by a small mortar shell. A single large rocket inflicts damage equivalent to that of a large mortar shell.
Rocket launchers can range from a single tube that launches a single rocket and can be carried by one person to more than a dozen tubes mounted on a truck or towed by a jeep. These multiple rocket launchers can produce a downpour of explosives. The rockets themselves can be a few inches in diameter and 4 or 5 feet long, all the way up to 12 inches in diameter and 15 feet long. Depending on how they are launched, rockets can be either direct fire weapons (a specific target is sighted) or indirect fire.
Missiles are similar to rockets, but typically missiles can be guided after they are released, which makes them far more accurate. A missile can home in on its target by being programmed to follow a laser beam shined on the target, or the missile can be controlled by someone who monitors its trajectory by using a TV camera in the missile. That person manipulates the missile by using a joystick. Like rockets, a missile can be launched from a single tube or from multiple tubes. They are often mounted on trucks, helicopters, and airplanes.
Grenades include hand grenades, those small, oval devices that weigh about a pound and are thrown at a target after a pin is pulled. Grenades can also refer to grenade launchers. These can be weapons used by individuals, or they can be mounted on vehicles and fed by crews. The individual grenade launcher looks like a single-barrel shotgun that propels what looks like an oversized bullet. Grenade launchers can fire many different things, such as flares, tear gas, or high-explosive shells.
A rocket-propelled grenade can be an individual's weapon, but it is more likely to be operated by a team. A projectile, weighing several pounds and about the size of a soft-drink can, is mounted on, not in, a tube. The shooter pulls a trigger, and the projectile is launched. Compared to a rocket, it doesn't go very far or very fast, but it goes a lot farther and a lot faster than a hand grenade. A rocket-propelled grenade can travel several hundred feet and do the damage of a stick of dynamite.
Explainer thanks John Pike of GlobalSecurity.org and reader Noah Meyerson for suggesting the question.