Properties of Water

    1. Occurs in all three phases
        solid (ice)   liquid (water)     gas  (vapor)

    2. It gains and loses energy slowly

    3. Its solid phase (ice) is less dense than its liquid phase.

    4. Water is a polar molecule.  (It has a slight electric charge)
        Its molecules tend to stick together.

Surface tension occurs because water molecules attract each other.  When a force pulls one molecule, others follow, like beads on a string.

Water can dissolve many other substances.  It is known as a universal solvent.  Polar molecules are soluble in water.  Non-polar molecules are not.

The Water Cycle is the movement of water continuously from one place on earth to another.

The sun's energy drives the water cycle.

Water has three phases:
liquid                    solid                    gas
water                    ice                        water vapor

Phase changes:
evaporation - liquid to gas
                   water  to  water vapor

condensation - gas to liquid
                      water vapor to water

Precipitation - water falling from the atmosphere - collection, underground water, rivers, streams, lakes.

Running water may cause weathering and erosion.

Evaporation can happen at any time during the water cycle.

It is important not to waste fresh water.

Water is essential to all living things.  Human beings are about 68% water.

Humans and animals "cycle" water through their bodies.

Photosynthesis - plants use light, water, and carbon dioxide to make sugars.

Transpiration - water moves upward through a plant and exits into the air through tiny holes in leaves.

People use water
Manufacturing processes use water (indirect use)
Animals use water

Sources of water:  wells, lakes, reservoirs, rivers, streams

Our use of water is part of the water cycle.