Properties of Water

1
Properties of Water

• Earth has the same amount of water as there was
  when Earth was formed The water from your faucet
  could contain molecules that dinosaurs drank.

2
How much water is there?

• Nearly ¾ of the Earths surface is covered by
  water.
• 97 of this is salt water
• Another 2 is locked in Ice-caps and glaciers
• 1 is for human use

3
How much do we use?

• A person can live a month without food but only
  about a week without water.
• Average US water use per person is 50
  gallons/day.
• The US uses more water than any other country,
  90 of it is used for industry and agriculture

4
Why is water the Universal Solvent?

• Its structure allows it to be the universal
  solvent. The molecule forms a V shape with the
  oxygen being the base and the two hydrogens
  making up the two legs.
• This structure creates a polar molecule. A polar
  molecule has two poles with partial charges. One
  end of the molecule is slightly positive while
  the other end is slightly negative.
• The polar characteristic of a water molecule is
  the main reason that water is such an excellent
  solvent.

5
Structure of Water

• Molecules in solid or liquid water are linked by
  hydrogen bonding
• Between 4-8 molecules make-up a group
• Ice consists of water molecules formed in
  hexagonal patterns
• Because of this pattern it expands in volume when
  it freezes and thus becomes less dense and allows
  ice to float, become more buoyant.

6
Physical Properties

• At room temperature, water is transparent,
  odorless, tasteless, and almost colorless.
• Any observable odor or taste is caused by
  impurities such as dissolved minerals, liquids,
  or gases.
• Because of hydrogen bonding, and attraction
  between water has high surface tension
• Important Solid water is buoyant in liquid water

7
How does dissolving happen?

• What do you think happens when dissolving occurs?
• The dissolving of a solid in a liquid occurs at
  the surface of the solid
• The moving solvent molecules cluster around the
  solute molecules. The negative ends of the
  solvent are attracted to the positive ends of the
  solute.
• The moving solvent molecules spread the solute
  out equally throughout the solution
• This process is repeated as layer after layer of
  the solute is drawn into solution until all of
  the molecules are evenly distributed.
• link

Factors Affecting Dissolving Rate
8
Water Filtration and Purification

• Natural purification and filtration
• Infiltration and Percolation
• The ability of a natural system to regenerate
  itself and maintain good water quality is
  affected by
• Concentration of impurities
• Speed and amount of water
• Materials water flows through
• Steepness of the land

9
Water Filtration

• Make Your Own Water Filter
• Materials Needed
• Water bottle cut in half
• Coffee filters, napkins or paper towels
• Charcoal, gravel, sand and cotton balls for your
  filter
• dirty water, you can make it by adding cooking
  oil, food coloring, pieces of paper, and tiny
  pieces of Styrofoam to water
• Water Instructions
• Make your own dirty water.
• Record your unique mixture as part of your
  observations of this lab.
• Also record the physical properties of your
  water, odor, color texture, presence of solids,
  etc.