the hand held can opener?

Question

QUESTIONS:

explain its uses and different types?

what are its predecessors?

what makes this device work?

what are the scientific principles behind this technology?

what is the science that makes this technology function?

Answer 1

see: http://www.ideafinder.com/history/inventions/canopener.htm
http://en.wikipedia.org/wiki/Can_opener
http://en.wikipedia.org/wiki/Pocket_knife

The initial can openers were either hammer and chisel or hammer and knife. When cans became thinner, the can opener currently found on Swiss Army knives were developed, which is basically a lever than pivots on the rim of the can and a sharp edge that punctures and cuts a small slit in the can top. By repositioning and repeating, the can can be opened.