A versatile and transportable laboratory apparatus was developed for middle and high school (6th-12th grade) students as part of a hands-on outreach activity to estimate catalytic rates of hydrogen peroxide decomposition from oxygen evolution rates measured by using a volumetric displacement method. The apparatus was constructed with inherent safety features and is compatible with different types of catalysts, catalyst and peroxide concentrations, and reaction temperatures to enable the design of various experiments. The hands-on outreach activity was created with the aim of building scientific proficiency and stimulating interest in STEM fields among students with limited chemistry background. This activity is designed to be completed in short times (45 min) by students in small groups (3-5 students), where each group measures reaction rates at various activity stations and then gathers as a larger group (~20 total) to discuss their observations and results and to assess their scientific understanding. Additionally, the activity is incorporated into a broader outreach program that uses hydrogen peroxide reactions as an underlying theme to introduce fundamental concepts in catalysis and kinetics to K-12 students. The program can be tailored to emphasize specific scientific topics including medicine, energy, or the environment.