Students in introductory college science courses often have a simplified understanding of the scientific method. To introduce students to the complexity of the scientific process and the value of empirical observations, I implemented a semester-long assignment that required introductory-level college science students to build and calibrate weather instruments from household materials. Students built their choice of a thermometer, barometer, hygrometer, or an anemometer, with a calibrated scale to record changes. Students then observed weather with their instruments for a period of 5 days and wrote reports on their instruments and observations. I evaluated these reports to determine how well students engaged in the scientific processes, including experimentation with their instruments and analysis of their data. Assessment data suggests this assignment successfully engages students in the process of scientific inquiry and helps them gain research experience as well as a better understanding of what goes into empirical observations. It also has potential to help students build quantitative skills in data analysis and interpretation. The exploratory structure of this assignment could be successfully adapted for use in introductory-level courses in other science disciplines.