Throughout history, people have used many methods to clean their teeth. Some ancient people chewed on frayed twigs. Others rubbed their teeth with cloth or swabbed them in vinegar. The Egyptians may have been the first people to use toothpaste when they mixed powdered pumice (a porous rock formed in volcanic eruptions) with vinegar and applied it to their teeth in the 100's B.C. Some toothpastes still contain pumice, but science has since supplied other toothpaste ingredients that the ancient Egyptians never dreamed existed.
Magnets are used in all kinds of applications, but do you ever wonder exactly why it sticks to certain metals? Find out the answer to this and other questions as we explore exactly how magnets work.
Booze, hooch, devil's brew. Whatever name you call it, alcohol is really just a combination of carbon, hydrogen and oxygen molecules. Test your knowledge of this simple compound with our quiz!