Where Does Water Come From?

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Where Does Water Come From?
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What is an atom?

• Simplest part of an element.
• Protons charges
• Neutrons no charge
• Electrons - charge

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Atoms form molecules by bonding covalently.
Hydrogen and Oxygen atoms covalently bond to form
a water molecule.
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Properties of Water
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Molecular Structure Polarity

• Water is a "polar" molecule, meaning that there
  is an uneven distribution of electrons resulting
  in a molecule with a both a positively and
  negatively charged region.
• In other words, the electrons are not shared
  equally.

Covalent Bond
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Hydrogen Bond

• Positive charges on one molecule and negative
  charges on another molecule attract each other
  and form hydrogen bonds.

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View the video on Polarity and H Bonding!

• Click on the bucket of water below to watch the
  short animation on water.
• Click on NEXT when you are finished.

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Cohesion

• Due to waters polarity, water molecules stick to
  each other forming hydrogen bonds!

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Adhesion

• Due to polarity, water sticks to other surfaces
  as well (unlike substances, opposites attract).

Meniscus
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Capillary action/Low Viscosity

• Due to polarity, water is able to move through
  small spaces, against gravity.
• Cohesion and adhesion are also seen in this
  property.
• This helps move water to the tops of tall trees
  and through veins in humans.

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Surface tension

• Due to polarity, hydrogen bonds form at the
  surface of water, forming an elastic film.
• Things that are light enough like water bugs can
  live and exist in an ecosystem on top of the
  water.

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Density

• Unlike most substances, water becomes less dense
  when it freezes.
• H bonds first condense when water is cold but
  then expands when water freezes leaving air
  pockets between the water molecules.
• Ice floating acts as an insulator to water in a
  body of water so fish dont die in the winter.

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Density

• Cold water is more dense then hot water.
• Cold water sinks (H bonds condense)
• Hot water floats (H bonds expand)
• Cause of currents in ocean different life found
  at bottom of ocean compared to top.

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Solubility/Universal Solvent

• Because of waters polarity, it is a universal
  solvent (can dissolve many things)
• Solute is the material being dissolved in a
  solution.

Animation of a solution forming
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Due to polarity, waters opposite charges attract
to the opposite charged ions in salt.
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Dissolving (solvent and solute forms a solution)

• The slight positively charged areas of the water,
  surround the Cl- parts of the salt.
• The slight negatively charged areas of the water,
  surround the Na parts of the salt.
• This property aides in the process of digestion.

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High Specific Heat Capacity(Temperature
Moderation)

• Water takes a long time to heat up and cool down.
• This is because heat energy is first used to
  break H bonds, leaving less heat energy to
  increase movement of the molecules which is
  necessary to increase temperature.
• This property helps maintain homeostasis (body
  temperature) and prevents bodies of water form
  changing drastically, effect life in it.

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pH (potential hydrogen)

• Solutions are either an acid (below 7), base
  (above 7) or neutral (7).
• Due to the dissociation of water, H2O can break
  apart in a solution and become H (making a
  solution acidic) or OH- (making a solution basic)
• If there is an equal amount of each ion, the
  solution is neutral.
• Water being neutral
• prevents tissue from
• being damaged in living
• things.