Measuring Clarity: Al-Siddiq International Middle School Students Learn Water pH Testing During ESNO 2025
The morning air in the main hall of Pondok Pesantren Umar Bin Khottob Plus, Gunung Malang, still carried the chill of the highlands. At exactly 7:30 a.m., dozens of students from Al-Siddiq International Middle School sat in a semicircle, each holding a bottle filled with water collected from Mata Air Ciburial—a spring they confidently described as clearer than branded bottled water. Amid the bustle of the Educational Students Night Out (ESNO) 2025, science class took an unusual shape. Instead of desks and whiteboards, students attended a presentation on water pH testing delivered by their Science teacher, Mr. Muhammad Fathul Ihsan, M.Res. With a calm but firm tone, he began with a disarming question: “If water looks clear, does that always mean it’s safe?” A low murmur swept across the room—curiosity awakened. Mr. Ihsan explained the fundamentals of pH, how acidity and alkalinity determine water’s potability, and how natural springs can still carry unseen contaminants. He demonstrated color changes in pH indicators, weaving scientific principles with everyday examples. The session was concise, visual, and sharply focused—Tempo-style clarity in a classroom setting. Holding up the Ciburial sample, he reminded them, “Clarity doesn’t guarantee purity. Science helps us see what the eye cannot.” Students inspected their water samples—comparing clarity, hue, and scent—turning the hall into an impromptu open-air laboratory. Although full testing would take place once they returned from ESNO, excitement was already visible. Each student would later conduct their own pH measurement back at school, using universal indicators or simple pH meters. The follow-up activity was designed not just for observation, but for students to experience the scientific process firsthand. Outside the hall, the noise of ESNO continued. Inside, attention remained fixed on a bottle of mountain spring water, a pH indicator, and a curiosity sharpened by real-world exploration.By Umair Shoddiq, S.I.Kom











