What is STEM? 
This is the most frequently asked question by teachers.  The short answer is that there is no single definition or practice that fully captures what it means to our students and to you.  In truth, it's different activities in different parts of school and the district.
STEM in the Classroom:
When many teachers think of STEM, they think Problem Based Learning (PBL).  While it is true that PBL features prominently in much of the STEM literature, it's not the only way towards developing a STEM-focused unit or classroom. Here are some most frequent key words I've found in research, teacher blogs and discussions with experts:
Application. Are your students applying what they have learned to real world problems?  Do they use the results of their work to re-focus and re-apply it for an improved attempt? 
Engagement. Are your students working on problems important to them and their community?  When the outcomes of there work have public value, they quickly recognize that 'getting to solution' has immediate and important consequences.  The intensity of this process, where students may interview local officials, work with experts in the field, and research the problem in detail allow them to become experts themselves. 
Design.  Do your students create their own approach to a problem?  This can be a math problem, a challenging photograph or a planning process for raising more vegetables.  Design processes are circular and doing so requires that students create a process, analyze the results, make changes to the process, and try again. This re-iterative method builds applications skills and a focus on data analysis.  
Rigor. Are all of your students challenged?  Do your problem solving exercises 'build' to more and more challenging applications?  Rigor is not 'making it hard', rather, it's about providing the next step to mastery.  Do your lessons carry students through a series of content and skills that allows them to apply their learning to novel problems?  Mindstorm robots do this naturally.  Students begin with short codes for basic movements and soon, they students apply these sequences to solve more and more complex movements.  This is no different from learning how to use graphs to analyzed data or an equation to solve a set of problems. 
By now you're saying: "That's me!  I do that!"  And you do.  But if you're like me, I could not make every day is a full on STEM day.   What I do know is that the more I asked students to apply what they knew, design their own process, contact local experts and build their skills to reach a creative level of application, the more they learned and the less I "taught'.  
Please do check out the STEM documents page for teachers and do connect to the STEM Blog.   I'll be updating the blog often to provide you with up-to-date research, grant possibilities and STEM news in the district and beyond.