_____________________________________________________________________________________________________ *Corresponding author: E-mail: opiopeter99@GMAIL.com, opiop@mmu.ac.ug; Phys. Sci. Int. J., vol. 27, no. 6, pp. 34-40, 2023 Physical Science International Journal Volume 27, Issue 6, Page 34-40, 2023; Article no.PSIJ.109466 ISSN: 2348-0130 Influence of Thermodynamic Arrow of Time on Entropy Opio Peter a* , Akullo Lydia b and Bwayo Edward c a Department of Physics, Faculty of Science, Technology and Innovations, Mountains of the Moon University, P.O. Box 87, Fortportla, Uganda. b Department of Physics, Faculty of Science, Uganda Matryrs University, P.O. Box 5498, Kampala, Uganda. c Department of Physics, Faculty of Science, Muni University, P.O. Box 725, Arua, Uganda. Authors’ contributions This work was carried out in collaboration among all authors. All authors read and approved the final manuscript. Article Information DOI: 10.9734/PSIJ/2023/v27i6809 Open Peer Review History: This journal follows the Advanced Open Peer Review policy. Identity of the Reviewers, Editor(s) and additional Reviewers, peer review comments, different versions of the manuscript, comments of the editors, etc are available here: https://www.sdiarticle5.com/review-history/109466 Received: 06/10/2023 Accepted: 08/12/2023 Published: 11/12/2023 ABSTRACT 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. Original Research Article