The project revolves around the energy produced in various types of chemical reactions (a key concept in all chemistry classes) and asks students to propose a useful source of chemical energy after engaging in a series of hands-on experiments and online activities. I appreciate how this project not only requires students to think deeply about their experimental results, but also how it asks them to apply them in a new context. Students not only collect and analyze data, they must seek a useful purpose or application of their results, giving the project real-world relevance.
This looks to be a good resource for K-12 inquiry-based projects that focus primarily on math and science (though there are connections to social studies and language arts). It is searchable by grade and subject.