Many people tend to assume that cans and can openers were invented around the same time, as it is now considered essential to have a can opener in order to open a can. This is not, in fact, the case: cans were invented in the early 19th century, in order to store food for the navy, while can openers weren't invented until a man named Ezra Warner came up with the idea half a decade later. In the meantime, people had to come up with creative ways to open the cans, often using sharp knives, or a hammer and chisel.

The can opener we all know and love today dates back to 1925, although it was only a minor modification to the original 1870 design, adding a jagged edge to the cutting wheel. It is a testament to their utility that the only change since has been the introduction of electric can openers, but electric can openers are still by no means ubiquitous, and it is rare to find a kitchen that doesn't possess a can opener in the classic design

Even though pull-to-open cans were invented 50 years ago, people still open millions of cans every day using can openers, as cans are much cheaper to manufacture when they don't include a ringpull. There is also a certain nostalgia value in opening a can with a can opener if you haven't done it for a while - although it can also be a little dangerous if you cut yourself on the sharp metal edge of the can's top.

However, the classic wheel design is not the only kind of can opener around. Another one that is very common is the P-38 pocket can opener, used in the army and often given out with food aid in the developing world. It is much cheaper to make than a normal can opener, as it uses much less metal, consisting only of a metal blade with a 'hook'. For the experienced, it can even be much faster to use than a normal can opener, and it is certainly easier to carry and store.