When we write the old-fashioned way, with ink on paper, we rarely think of the pen’s ingredients. For hundreds of years gall ink was used to produce documents such as Shakespeare’s will and the U.S...
The first ever toothbrush design, used by ancient Babylonians and Egyptians, dates back to 3500 BC. The primitive toothbrush, known as a “chew stick”, was a thin twig with a frayed end. The modern...
The green in American paper bills is chromium oxide, a refined version of chromite, a naturally occurring ore in the Earth’s crust. This ore is also the source of chromium metal which is produced...