PBS is undertaking a multi-year initiative to recognize excellence in pre-K through 12th grade educators and practices in science, technology, engineering and math (STEM). The PBS Teachers Innovation Challenge was announced today, as President Barack Obama spoke at the White House on the second phase of its Educate to Innovate campaign. “America’s leadership tomorrow depends on how we educate our students today, especially in science, math and engineering,” the president said, praising the numerous partnerships that include PBS. The National Science Teachers Association is encouraging educators to participate in PBS’s Challenge. Fifty winners will be announced this spring.