/oss/taxonomy/term/971/all en /oss/article/general-science/how-do-erasers-work <p>These days we are accustomed to pressing the delete key and a word on the screen disappears, ready to be replaced by a few keystrokes. But that doesn't mean pencils and erasers have disappeared. On multiple-choice exams, little circles are still coloured in with pencils and if a mistake is made, an eraser is needed. Let's glimpse into their history...</p> Thu, 09 Jun 2022 20:52:06 +0000 Joe Schwarcz PhD 9132 at /oss /oss/article/technology/under-microscope-graphite <p>Pencils do not contain any lead, and they never did! The mistake in terminology can be traced back to the ancient Romans who drew lines on papyrus using pieces of actual lead, all the while not realizing it was incredibly toxic. Considering its toxicity, it’s really good that pencils never did contain lead. Could you imagine how much a child could ingest while chewing on their pencil?<br /></p> Mon, 08 Apr 2019 16:15:44 +0000 Ada McVean B.Sc. 7700 at /oss /oss/article/history-science-science-everywhere-you-asked/what-link-between-diamond-graphite-and-buckyballs <p>They are all composed only of carbon. What determines the properties of any substance? Simple. The properties of any substance depend on the type and number of atoms they are composed of, and of course on how those atoms are joined together. Water and hydrogen peroxide, for example, are both composed only of hydrogen and oxygen, but a molecule of hydrogen peroxide has two hydrogen atoms and two oxygen atoms while water of course has two hydrogens and one oxygen. So even though they have the same components, they have dramatically different properties.</p> Fri, 26 Apr 2013 00:50:42 +0000 Joe Schwarcz PhD 1917 at /oss /oss/article/did-you-know/pencils-never-contained-lead <p>This may come as a shock to some people but lead pencils do not contain any lead.  Never did.</p> Thu, 23 Feb 2017 03:20:30 +0000 joe Schwarcz PhD 1523 at /oss