## On Change

We all know that we leave in a three-dimensional world. Up-down, right-left, forward-backward – these are well-familiar to us directions in three dimensions of space we occupy. However, we also live in a three-dimensional world of another kind. In physics, we have units of measurement. There are lots of them, but only three are fundamental – all other are various combinations of these three – meter, second and kilogram (yes, in science, we use metric rather than Imperial units). We measure space in meters (m), we measure time in seconds (s) and we measure mass in kilograms (kg). These three units are fundamental in a sense that they are irreducible and all other units are combinations of meter (m), second (s) and kilogram (kg) (please note that in this context, kilogram is not [...]