Engaging students in authentic scientific processes is a big difficulty for physics instructors. Because physics is inherently an experimental science, our laboratories can be a good place to do it. However, the purpose of experiments is often to demonstrate a principle that the students have already learned, and the emphasis is on quantitative data analysis with plenty of instructions on how to carry out the experiment. This method is at odds with the scientific approach. The AAPT lab recommendation has proposed six learning outcomes related to experimental activities. While some of these objectives can be developed with the traditional “cookbook” method, such as developing technical and practical laboratory skills, others will not. This is especially true for the two learning outcomes at the heart of the scientific process: 1) designing experiments to test models and hypotheses and 2) presenting results and ideas with reasoned arguments supported by experimental evidence. Several approaches have been developed to deal with this problem. However, these approaches are often very time consuming and require a complete overhaul of the way teaching is organized. The need to make such changes is a barrier to the adoption of these methods. How can we develop in our students the ability to test models and then argue based on experimental results, without revising the entire organization of our laboratory teaching? We propose here a method called small lab debates (SLD) that allows students to regularly engage in short activities —about 20 min— involving an experimental scientific approach. Our method is inspired by peer instruction, and just as the latter can be easily implemented during lectures, SLD can be easily integrated into any session in a lab or on a simulator.