Water = Life

Hi all,

Today, we examined the amazing properties of water - that tiny little molecule with the special properties that is the foundation of all life as we know it.  Philip Ball, a scientist whose specialty is water, has said that "Water is life's true and unique medium.  Without water, life simply cannot be sustained."  Water is so intricately linked to life that when astrobiologists go searching for other planets that might harbor life, they follow the water - any planet with liquid water is a likely candidate for life.  Unfortunately (fortunately?), those planets are quite rare.  Most planets either orbit too close to their star, creating high temperatures that cause any water that might exist to boil off, or orbit too far from their star, so that any water that's lying around is frozen and therefore inhospitable to life.  Earth has the "Goldilocks syndrome" - it's juuuuuuust right, wedged in that sweetspot distance from the sun so that our atmospheric temperature is between 0-100C, and liquid water can exist.  And look at all the life we've got!  If we're talking about the stuff of life, water is some important stuff.

Water is oh-so-amazing because of hydrogen bonding, and most of its properties can be traced back to this phenomenon.  Adhesion, cohesion, surface tension, high specific heat, and polar solvency can all be traced back to the strong hydrogen bonds water forms with its own molecules and with other charged molecules like it (we call those molecules that can hydrogen bond with water polar or hydrophilic).  Below, I've posted one of the best animated tutorials on water and life out there - check it out when you have a chance as a review:

Properties of Water Tutorial

Homework
R4 - view animation above, and work on assessment statements.

R6 - revise Lab #1 based on our discussion today, and view animation above; continue to work on assessment statements