The first reliable spark plug was invented in 1903 by Oliver Lodge. They're aptly named as well; spark plugs are simply insulated plugs that are screwed into an internal combustion engine's cylinder head to deliver the spark that ignites the mixture of air and fuel in the combustion chamber.
Are Irish Twins Technically Twins? Irish twins are not technically twins, meaning two people born from the same gestational period. It's a colloquial way to classify siblings that are born close together. Sometimes the use of the term Irish twins is expanded to describe any siblings that are close in age. Some even stretch the definition to include siblings less than two years apart. Some would call that almost Irish twins or practically Irish twins..
Twins are a wonder of nature. There are basically two types of twins, defined by their genetic relationship: identical twins (monozygotic twins) and fraternal twins (dizygotic twins).