In the popular media, you often hear the phrase “the ‘something-or-other’ has grown exponentially.” Quite often in such situations, the word ‘exponentially’ is used imprecisely to mean ‘quite a lot’ or ‘rather fast’, but in science it has a very specific meaning. Exponential changes happen when the rate of change of a quantity is proportional […]

Fukushima in Japan has become newsworthy again recently. Many residents have been allowed back to their homes. In January 2019, Scientific American reported that radiation: “in some places continues to measure at least 5 millisieverts (mSv) a year beyond natural background radiation, five times the added level Japan had recommended for the general public prior […]