Shot put and hammer throw originated in the Celtic culture, they were not held during the Greek games - but appeared with the first modern Olympics in 1896. The competition to see how far one could lob a heavy weight, in this case the shot put, was refined from throwing a round heavy stone.
The shot itself is a ball usually made of lead
or some other metal
of varying weight depending on your level.
High school and college girls (varsity, JV): 4 Kilograms
High school boys (Junior Varsity): 10 Pounds
High school boys (Varsity): 12 Pounds
College men: 16 Pounds
The shot must be put, not thrown. If you try to throw it like a baseball you'll most likely pull a muscle or bust a tendon or something. The shot has to come off before your elbow. The best way to put the shot is by using the stretch reflex of your latissimus dorsi muscles and your quadriceps by standing against the toeboard of the ring, roughly 4' in diameter in high school, with the toe of the front foot aligned with the instep of the back foot, the shot held along the bridge of the hand and tucked against the neck, with legs bent.
Then the thrower (we're called throwers, but the only thing we really throw is the discus) torques up by winding the upper body to face the back of the ring. Next he/she/it twists the hips, using the ball of the back foot, pulls the free arm back from an extended position to pulled in tight against the body with the elbow at a 90 degree angle (known as blocking, and finally adds the strength of the arm to the put. In order, the hips, quads, lats, and finally upper arm is used to propel the shot. The thrower cannot touch the area outside the front half of the ring, and must exit from the back under control.
If you watch the Olympics, you'll see the competitor spin or almost hop across the ring, but the final position before throwing is the one described above - the power position. The glide, which looks like hopping on one foot, involves leaning slightly forward, bending down over the back foot (the one which belongs to the hand the shot is in), pushing across the ring while turning 90 degrees, landing in the power position, and then putting. The objective is to add as much momentum to the linear motion of the shot as possible.
As you can see, throwing takes more coordination, grace and practice than it seems. Strength doesn't get you nearly as far in the throwing, or weight events, as technique does - but strength is definitely needed. There are a bunch of little things I did not include in this node -- keeping the shot centered over the knee, for instance, or the angle you take when you block, where your chest should face when you finish (up, in case you're a weight guy and your coach doesn't know this), etc. Shot put is a highly technical event, and the feeling you get when you finish a great throw and watch your shot land in a spray of dust fourty to fifty feet away (which is, by varsity standards, pretty good at the beginning of the year - excellent by JV standards at the end) is as gratifying if not more so than watching your competitors stream in behind you in a similar trail of dust as you finish a 100, or a mile, or whatever the crazy running people do.
Dziepak, Tony. "The Thrower's Page." http://www.geocities.com/Colosseum/8682/