If electrical plugs had only one prong, nothing would happen. Electricity would not complete a circuit. Nothing would work.
You will need to replace the 3-prong outlet with a 4-prong outlet to match your dryer cord. Alternatively, you can replace the cord on your dryer with a 3-prong cord that matches the existing outlet. Make sure to consult a professional if you are not comfortable with electrical work.
This is something that should not be done. If this was to be done you would be omitting the ground which in point can make it unsafe. I recommend changing the female end of the system and making it a 4 prong.
The difference is safety. Any appliance or equipment that has metal parts that may be touched by the user will usually have 3 prongs because this provides for safety if those metal parts become energized. Exceptions would be "double insulated" items, such as many power tools, and items without exposed metal parts.
The 6-20 is a designation for a 20 amp circuit. Most homes have receptacles rated for 15 amps. The cord is designed so that you cannot plug it into a 3 prong 15 amp outlet for safety purposes. The wire, fuse or circuit breaker as well as the receptacle must be properly rated so you don't burn your house down. Proper inspection and possible rewiring to the power panel is needed to operate it safely.
That is one simple question that can't have any simple answers! For a start, do you mean "the history of electrical outlet changes" just for one country (such as USA or England, or Australia, or ...) or do you mean worldwide? One way for you to get some answers to this question would be to go to a science museum and ask if there is a section dealing with the history and development of electricity supply systems. Or you could go to your local library and ask one of the staff there to suggest some books for you to read that cover this subject!
If there were no bottle caps (as we currently know them), there would be covers or plugs of some type. For example: cork or wax or plastic plugs. Someone would invent something to protect the contents of a bottle.
This is very strange indeed. All modern houses in USA would have 3-prong outlets. I can't see how it could pass an electrical inspection. Check with the local agency who does inspections. Check your electric panel and look for an inspection sticker. I have encountered receptacles that are very hard to use because one or more of the pin slots (I don't know what else to call them) are way too tight. There is no easy remedy for this problem except to press hard to get the plug into the receptacle or replace the receptacle with one of a better quality. There are also child protective receptacles that require that two or three of the pins be pressed in at the same time or none of them will go. If the plug is just slightly off true it won't go.
a spearfisherman
Because there is no path for the electricity to return with only one prong. Electricity needs a complete path to flow through. If you were to grab a hot prong and the electrical source then that would work, but I don't recommend it.
You will need to replace the 3-prong outlet with a 4-prong outlet to match your dryer cord. Alternatively, you can replace the cord on your dryer with a 3-prong cord that matches the existing outlet. Make sure to consult a professional if you are not comfortable with electrical work.
it also carries curent from the outlet
Generally yes, but it depends on the building codes in your area. Homes that have not been updated may have the older two prong sockets. All newer homes will have the three prong or grounded sockets. Any new construction would require three pronged sockets.
This is something that should not be done. If this was to be done you would be omitting the ground which in point can make it unsafe. I recommend changing the female end of the system and making it a 4 prong.
the engine is constantly vibrating and it dislodges the spark plugs
I would recommend the OEM spark plugs, AC/Delco. Excellent plugs.
If a prong off a plastic fork broke and you swallowed it, it is unlikely that it could hurt you. Something so small would most likely pass through the bowel in the feces.
i would recommend ngk iridium plugs