School science labs often fail because they aren't inquiry based, at least not based on the questions the students have. If not, they did something wrong. The challenges must have clear goals. In solving the challenges, teams must have control over their designs and methods. Without control, it is your solution, not theirs.
Feedback is immediate.
Participants know when they have a great new idea and don't need external evaluations to feel good about their project. It is not a coincidence that these characteristics of the inventing laboratory are the same as those for any enjoyable experience. Our goal is to make learning an autotelic experience. By structuring the learning environment as an inventor's laboratory, we provide students experiences they want to continue. That is, they don't want to stop working on their inventions and don't want to stop learning the skills and knowledge they need to make their inventions work.