When schools around the world closed their doors due to the coronavirus pandemic, the team behind MIT App Inventor — a web-based, visual-programming environment that allows children to develop applications for smartphones and tablets — began thinking about how they could not only help keep children engaged and learning, but also empower them to create new tools to address the pandemic. In April, the App Inventor team launched a new challenge that encourages children and adults around the world to build mobile technologies that could be used to help stem…