Looking back at some of the most significant technologies humans have invented, the humble pencil is likely at the top of the list. For centuries, it has allowed people to record their thoughts and ideas and share them with the rest of the world. For its latest act, the pencil could also enable people to monitor their health. A team of researchers at the University of Missouri has published a study that details how they used the tool to create bioelectric monitoring wearables.
It turns out pencils with cores made from more than 90 percent graphite conduct a significant amount of energy when you use them to write on office supply paper. The graphite can double as a sensing electrode, while the paper provides a flexible supporting structure. The team found pencils with 93 percent graphite content worked the best.