On this day (30 April) in 1897, Joseph J Thomson announced the discovery of the electron. It was the first time a subatomic particle had been discovered. This graphic takes a quick look at his discovery; for a more detailed explanation, check out this Institute of Physics article. For more on different models of the atom over the years, there’s this graphic highlighting key theories and models.
All matter is made up of atoms. This is something we now take as a given and one of the things you learn right back at the beginning of high school or secondary school chemistry classes. Despite this, our ideas about what an atom is are surprisingly recent: as little as one hundred years ago, scientists were still debating what exactly an atom looked like. This graphic takes a look at the key models proposed for the atom, and how they changed over time.
Today, 23rd October is Mole Day – which might put you in mind of small, furry, burrowing animals. However, they don’t even seem to have a commemorative day of any kind; we’re actually talking about the mole in chemistry, a concept that makes it easier to talk about the amounts of substances involved in chemical reactions. This is a fundamental concept and one that all chemists utilise.
