What Is A STEM Activity? Have you ever asked yourself what is a STEM activity? At Hess UnAcademy, we believe that STEAM and STEM activities for kids are an important part of a good education. Learn what a STEM or a STEAM activity is, what kinds of jobs that require a STEM education, why you should invest in a STEM curriculum, and find some popular STEAM and STEM activities for kids while you're at it.