This work describes the design, building, and testing of miniature, low-cost LED-LDR colorimeters for absorption-spectrophotometry experiments. It also describes using these colorimeters for simplified context-based-learning (CBL) activities in school teaching laboratories and for public-engagement events. The colorimeters are simple and robust, performing well against a conventional benchtop UV-vis spectrophotometer. Data collection and analysis is quick and intuitive, allowing for efficient turnaround between groups and making it particularly useful at public-engagement events. The experiments and activities described here are based on real-life examples to emphasize the usefulness of chemical analysis and quantification in everyday life.