Rainfall Experiment FAQ

Common questions about the Student Rainfall Measurement Experiment, grouped by topic. The attached PDF has the full set.

Getting started

No special equipment or money is needed — a straight-sided container, a millimeter ruler, a marker, and an open-sky spot. It is an individually run experiment (stations are not shared). Apartment dwellers can often take part if a balcony passes the distance test and the coordinator approves it. If you travel or fall sick, ask a family member to observe, or report those days as Missing — missing days are honest; invented numbers are not.

Equipment

Avoid cut soft-drink bottles (curved sides make the depth wrong) and always use an opening at least 10 cm across (a wider mouth catches a fairer sample). If a container breaks, tell your coordinator and register the replacement before switching. Never use a lid — the collector must stay open to the sky at all times.

Location

The distance test: keep the collector at least twice as far from an obstruction as the obstruction rises above it. Roof, tree, or wall water is runoff, not rainfall, and cannot be corrected afterward — only direct drops from the sky count. Roof placement is allowed only if you can reach it safely without climbing, no water flows across into it, and the rim is above splash height. For disturbance, tell neighbors what the experiment is, add a small "please do not touch" sign, and mark disturbed days Invalid.

Measuring

Measure daily even though you report weekly — water left a week evaporates, overflows, or collects debris, and daily readings tell us which day the rain fell. Use one shared time (8:00 AM, or another fixed time agreed with your coordinator) so every station's "day" covers the same hours. Read the ruler at eye level, not from above. Rain that falls after you measure counts for the next day.

Reporting and data quality

Zero means "I checked and there was no rain"; Missing means "nobody checked" — writing zero for a day you did not check is the single most damaging mistake. Use Questionable for minor doubts (slight tilt, debris, possible splash) and Invalid for serious problems (knocked over, runoff, tampering). Forgot a day? Measure now, record the actual hours covered, and never split or guess. You will never be in trouble for honest gaps — coordinators are trained to praise them.

Weather and safety

During lightning or dangerous storms, stay inside and measure when it is safe. If floodwater reached the collector, mark the day Invalid — but still note neighborhood flooding, which is valuable on its own. If wind tips the collector, mark that day Invalid, re-secure it, and improve the anchoring.

For coordinators

Handle suspicious data privately and kindly ("walk me through Tuesday"), aiming to recover an honest observer. Wildly different nearby stations may both be correct — monsoon showers vary sharply over short distances. Run at least eight weeks of live data (a full monsoon season is better). Consistently collected, honestly labeled student data can be used beyond the classroom, supporting Rainflower's youth-led rainwater preservation mission.

This is a summary. Download the attached PDF below for the complete, print-ready document. Grades 9–12 · Bangladesh · Student field research — measure carefully, report honestly, learn from local rain.