Spoiler Alert. Bungee cord and shock cord are the same thing. After reading several dictionary definitions for shock cord they went something like this. An elasticized cord made from strands of rubber (natural or synthetic) encased in a woven outer sheath made of cotton, nylon or one of the poly products. It is used for fastening, bearing weight or shock absorption and typically has a metal or plastic hook at each end. It was also called elasticized rope. Also, see bungee cord.
I looked for the origin of the name bungee and nobody seems to know for sure. It is spelled several different ways including bungee, bungie, bungy and bun-gee with bungee being the most popular. Several possibilities are British slang for India rubber may have been bungee or bungie. Another possibility was earasers made of a type of rubber for removing pencil marks from paper have been referred to as India-bungie. The Oxford English Dictionary says the phrase bungee-launching was used in 1938 referring to using elasticized cord to launch gliders.
Bungee cord or shock cord is made with either natural or synthetic rubber. Each material has advantages and disadvantages. Natural rubber (aka latex rubber) has the ability to extend and then come back to its original shape. It also has a high tensile strength which allows it to extend under a load without breaking. However, natural rubber does not resist air and light well. Synthetic rubbers like neoprene resist natural elements like sun and air but don't as well as natural rubber in returning to its original shape and have less tensile strength.
These cords are found in virtually every hardware store. They are sold individually, in bundles and in tubs containing multi size and lengths. Bungee cords usually have hooks attached to them. Bungee cord can be purchased in bulk without the hooks. My brother in law is a truck driver. He uses bungee cord to secure tarps when hauling flatbed loads. No hooks required for him, he has a way strapping his tarps without them.
Bungee cord is good for business, so says the eye doctor. It is responsible for a lot of eye injuries. I believe this comes mostly from over extension (extending or pulling the cord farther than it is supposed to stretch). If a bungee cord has an elongation rating of 100% that means it is meant to stretch twice its original length. Bungee cord can have longer or shorter elongation ratings. Used properly you shouldn't have a problem.
The sport of bungee jumping has been around for about 1,500 years according to some. It became popular in the 1970's. Since then it has evolved into a commercial sport. From my point of view this is how it works. You stand somewhere that is resonably safe. Then you tie a rubber band to your ankle and jump off the safe spot. It is not on my bucket list. I also have a thing about dangling from a string off a rock (rappelling) or from the bottom of a kite (parachuting). Another commercial use of bungee cord is to launch people up and down in a ride at a amusement park. I bet you have a clue on my thoughts on that.
The military uses bungee cord or shock cord to reduce the sudden impact when a parachute opens. Think of it like pulling a wagon with a rope. If the wagon hits something that stops it the jerk on the rope is virtually instant. The impact stops you right now. If you attach a spring to the wagon and your rope to the spring, you will still stop, but the impact will be slower and not an instant abrupt stop. This reduces stress on you, the rope and the wagon.
Some of the other uses of Bungee Cord or Shock Cord
Attach items to backpacks.
Tent guy lines.
Bundle or roll up sleeping bags or blankets.
Attach items to a cart.
Attach trampoline pad to frame.
Secure items to car racks or pickup beds.
Hang paper towel roll or any wire rack.
String from one back seat grab handle to the other. Hang entertainment items for small children.
Keep plastic or re-useable grocery bags upright preventing spills. Hook thru handles to either side of the car or to your head rest posts.
Working alone--use to hold up the other end of a long board. Attach your end and then position the other where you need it.
Repair lawn chairs with a lattice work of bungee cord underneath the cushion.
Fender bender--strap on loose car parts so you can get home.
Make a stuffed animal zoo. Brill holes along the front edges of the top and bottom of a small inexpensive book shelf. String the bungee cord vertically. Stuffed animals can be storeed behind the cord. The same type of idea can be used for soccer and basket balls with a little larger wooden frame.
A temporary clothes line.
Making a front facing magazine rack on a vertical. Magazines rest on a horizontal shelf with a horizontal bungee cord attached to the wall about half way between the shelfs. Magazines set on the shelf behind the bungee cord.
Repair a tent pole. The type that pull apart and fold up with stretch cord inside.
Attach gromets to an outdoor table cloth and secure underneath with bungee cords.
Replace shoe laces to make a slip-on pair of shoes. One piece of bungee per two eyelets. Tie a knot in the end, insert thru the two eyelets and tie the other end. Shorter pieces or more tension closer to the toes and reduce tension as you move up the shoe toward your ankle.
Chest strap for backpack. Insert under the shoulder straps against your chest and wrap each end around the shoulder straps and attach the bungee to itself.
Stop the trash liner from slipping into the receptacle by securing it around the top.
A barrier in front of shelves.
Attach vertically on wire shelves so you can store cookie sheets or baking pans in the vertiacl position.
There's plenty more just use your imagination.