Secondary 1 students Adbeel Yeo (left) and Cruz Chan (second from right), both 12, from St Andrew's Secondary School collecting water from the Kallang River to analyse its acidity and dissolved oxygen levels.
The sample Cruz drew had a surprising find.
"The best part of today was finding a small fish in the water sample," he said.
More than 30 students took part in the hands-on learning trail at the Kallang Riverside Park to pick up tips on water pollution, climate change and water conservation.
Jointly hosted by Singapore Press Holdings and environmental group Waterways Watch Society, the Kallang River is Living and Loved is a year-long education outreach programme targeted at students from the primary to tertiary levels.
It is expected to benefit at least eight schools and 8,000 students.
Schools can sign their students up for the learning trail, an assembly talk, or both.