Computer science unplugged (CS Unplugged, or just "Unplugged") is a pedagogy for teaching computational ideas to grade-school students without using a computer.a It was developed in the early 1990s as a necessity when working with computers in the classroom was not usually practical, but it still finds widespread adoption as a supplement to computer-based lessons, even where devices are readily available. This appears as a contradiction to some (if you are teaching computer science, why not spend as much time as possible on a computer?), while for others it provides a chance to reduce screen time, get physical exercise, and engage with students in a kinesthetic way. Unfortunately, Unplugged can also be used to justify poor decisions by treating it as a complete curriculum in itself—a teacher who does not have the time or support to extend themselves in new curriculum content might rely on Unplugged as "enough," or administrators might justify a lack of funding by suggesting that schools use Unplugged teaching instead of buying devices.
The Unplugged approach is widely used, mentioned in dozens of research papers about CS education, has been translated into many languages, and is widely used in teacher professional development.1 A number of studies have reported positively on its use. And yet there are those who have raised concerns about teaching computer science without computers (for example, Stager and Martinez7) since it appears antithetical to learning programming.