For the benefit of those who supposedly went to journalism school and got a college degree of some sort, I now present a couple of definitions. I see these words used incorrectly in news articles all the time and I think it's about time someone made mention of the fact that the items in question are not the same.
The two things people regularly confuse are the sling and the slingshot. Both are small, hand-held, projectile weapons. One is ancient whereas the other is rather modern. Each has its own method of construction and employment. Each is based on a different physics concept.
A sling consists of two cords, or strings, attached to a pouch. The user places a small stone or similar into the pouch and then grasps the ends of the strings that are not attached to the pouch. The user starts the pouch spinning through the air to build up momentum. When the pouch is at the correct place in its arc, the user lets go of only one of the strings. The pouch opens up and the rock inside continues forward toward the target. Commonly, the user ties a loop in the end of one of the strings and places this loop around the middle finger. The user ties a knot in the end of the other string and holds this knot to prevent premature release.
One makes a slingshot by attaching elastic strands to the two branches of a forked stick with a pouch attached at the other end of the two strands. The user places a small stone or similar into the pouch and pulls the pouch away from the forked stick. This pulling stretches the elastic strands. When the user releases the pouch, the elastic strands snap back toward the forked stick and propels the stone between the forks with great force, preferably toward the target.
People have been using slings for thousands of years. Photos often show Middle Easterners using slings in urban combat or just protests. You can easily make a sling from a bit of cloth and a shoestring. One can use manufactured projectiles, for better reliability and consistency, or use any solid object found on the ground. One could, hypothetically, launch kittens with a sling.
Slingshots require a source of elastic strands. Tire inner tubes used to be one of the best materials available in the United States. These are not as readily available anymore so surgical tubing has become the preferred replacement. You can find this tubing near any heroine addict. One does not need to construct one's own slingshot anymore; they are commercially available. These pre-made slingshots are often very powerful weapons capable of killing an animal at quite a distance. You can find them in any large toy store.
So, now you have no excuse. There is no reason for me to see a photo of a Palestinian boy holding two strings with a pouch at the end captioned "a protester uses a slingshot". Likewise, there should be no reference to the biblical tale of David using a slingshot to kill Goliath. There should, of course, be great concern if the comic character Dennis the Menace starts using a sling. These are two distinct kinds of weapons; please don't confuse them.
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