water has a very high surface tension, the force
holding the liquid surface together. This, along with
its ability to adhere to surfaces, enables the upward
transport of water in plants and soil by capillary action.
water (ice) has a lower density than liquid water at
the surface of the earth. If ice were denser than liquid
water, it would sink rather than float, and bodies of
water in cold climates would eventually freeze solid,
killing the organisms living in them.
comprises only about three percent of the earth's total water
supply and is found as either surface water or groundwater.
Surface water starts as precipitation. That portion of precipitation
which does not infiltrate the ground is called runoff.
Runoff flows into streams and lakes.