This study assessed the influence of thermodynamic arrow of time on entropy for boiled cooling water (physical process), the universe and the air (natural process). This was done by determining the entropies of boiled water, the universe and air. This was achieved by using 1.5 litres of pure water, a 2 liter electric kettle, a digital thermometer, a digital weighing scale and a stop watch. The entropy values of boiled water as it was cooling, was in negatives, that of the universe was in negatives and positives and that of air (natural process) was positive. This showed that for any physical process, (boiled cooling water and the universe) thermodynamic arrow of time does not influence entropy in the positive direction while as for a natural process (air), thermodynamic arrow of time influences entropy in the positive direction. The boiledcooling water was a non-spontaneous process, the universe was both non-spontaneous and spontaneous and the air was a spontaneous process. The study has shown that thermodynamic arrow of time influences only entropies of natural process in the forward direction but for the physical process, the entropy can be influenced both backwards and forwardwise.