Interstices are the gaps between things, as with the cells in your body or the spaces between architectural columns. When applied to time, it means the many bits of time scattered throughout the day such as the five minutes that students have in between classes, or the unknown number of seconds that pass while you are waiting for an elevator. These moments used to be given over to silent reflection or conversation with whoever is around. Now, for most of us, nearly all of them are grabbed by our phones.