Water covers more than 75% of
the surface of the Earth. While much of it is in the oceans, lakes
and rivers on the continents contain a lot of water as well. Water
is also the most abundant molecule in just about every organism on
It's easy to take water for
granted, but life changes drastically when water is either scarce or
plentiful. Droughts and floods can destroy crops and lead to food
shortages. Within our body, too little water can lead to death, and
too much fluid in the lungs or heart can be fatal.
In order to appreciate the
factors that lead to the scarcity or abundance of water in an
environment or in an organism, we need to understand the molecular
structure of water. Water's structure has important implications for
its chemical and physical properties, and we'll explore these in
detail in this Lesson.
Did you ever wonder why a water
droplet is spherical, and not some other shape? Or why table salt
dissolves in water, but cooking oil doesn't? These properties of
water are directly related to its chemical nature. As we learn about
some of the unique properties that make water an ideal solvent for
biological systems, we'll be focusing on the important relationship
between its structure and function.