My Favorite Equation

Earlier this week, I was asked what the most important thing I've learned in higher education, and I answered the following:

σ=Eε

In typically MSE terminology, this translate into words as stress equals stiffness times strain.  


E, Young's modulus, is one of the first ways we quantitatively characterize the way a material reacts to a stress (force/ unit area) or strain (change in net dimensions). The equation above assumes the material reacts uniformly in all direction, but even the more complete formula retains a simple elegance.


However, the real thing I've learned is this: being flexible under strain leads to less stress. If you've planned your day in 15 minute increments from the moment you wake up until bed, the extra homework assignment, or failed experiment you have to redo suddenly becomes more stressful.  The busier I get, the harder this is to remember, but it's better to be a bit flexible than break.