Staying after school every Friday afternoon might not sound too appealing, but it is irresistible to a group of middle schoolers in Pawtucket, R.I. The students are part of a club that focuses on science, technology, engineering and math, so-called STEM subjects, through hands-on learning. For one of the fall projects, they’re building and crashing small cars, trying to protect the passenger inside—in this case, a hard-boiled egg. There are hundreds of after-school STEM programs in the country, trying to interest students in these fields. One focus is getting more women, minorities, and low-income students into STEM classes and occupations. With the demand for skilled workers increasing, schools are under pressure to expand STEM offerings. It can be difficult to fit this into the school day, especially in the lower grades. So specialized after-school programs are aiming to fill the gap.