Design and Construction of Newton’s Law of Cooling Apparatus Featuring Digital Temperature Measurement and Data Logging Systems: A STEM Practical Aid

Abstract

This study presents the design and construction of a low-cost experimental apparatus for the demonstration and verification of Newton’s law of cooling using locally sourced materials. The apparatus was fabricated from a 2.0 mm thick mild steel sheet and equipped with an Arduino Uno microcontroller and DS18B20 digital temperature sensors for automated temperature measurement and data logging. To evaluate its performance, the cooling process of 50 mL of water initially heated to 90 °C was monitored until thermal equilibrium with the ambient environment was approached. Both the water temperature and ambient temperature were recorded automatically throughout the experiment. Analysis of the experimental data revealed a linear relationship between the rate of cooling and the excess temperature of the water above its surroundings, consistent with Newton’s law of cooling. The slope of the best-fit line was determined to be (0.0045 ± 1.87881) × 10⁻5 s⁻¹, with a coefficient of determination (R²) of 0.99189. The high degree of linearity obtained demonstrates the reliability of the apparatus and confirms its suitability for verifying Newton’s law of cooling within experimental uncertainty. Owing to its low cost, ease of construction, and automated data acquisition capability, the apparatus offers a practical alternative for teaching and laboratory demonstrations in educational institutions with limited resources.