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A Water Planet

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A Water Planet Learning about water and its properties. Aqua Earth holds an abundance of streams, rivers, lakes, and oceans of liquid water. – PowerPoint PPT presentation

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Title: A Water Planet


1
A Water Planet
  • Learning about water and its properties.

2
Aqua
  • Earth holds an abundance of streams, rivers,
    lakes, and oceans of liquid water.
  • Only planet that we know of where water exists as
    a liquid in any appreciable quantity.
  • Water covers nearly ¾s of the earths surface
  • Moves around constantly through evaporation,
    precipitation, and runoff that distribute
    nutrients, replenish freshwater supplies, and
    shape the land.
  • Water makes up 60-70 of the weight of most
    living organismsit fills cells, giving form and
    support to tissues.

3
Properties/Qualities of Water
4
Water molecules are polar
  • They have a slight positive charge on one side
    and the other side has a slight negative charge.
  • Thus, water readily dissolves polar or ionic
    substances, including sugars and nutrients, and
    carries materials to and from cells.

5
Predominant Liquid in Nature
  • Water is the only inorganic liquid that exists
    under normal conditions at temperatures suitable
    for life.
  • Most substances exist as either a solid or a gas,
    with only a very narrow liquid temperature range.

6
Water molecules are cohesive
  • They tend to stick together tenaciously.
  • Water has the highest surface tension of any
    common, natural liquid.
  • It is subject to capillary action it can be
    drawn into small channels.
  • Without capillary action, movement of water and
    nutrients into groundwater reservoirs and through
    living organisms might not be possible.

7
Water expands when it crystallizes
  • Most substances shrink as they change from liquid
    to solid.
  • Ice floats because it is less dense than liquid
    water.
  • Without this feature, many aquatic systems would
    freeze solid in the winter.

8
High heat of Vaporization
  • Water uses a great deal of heat to convert from
    liquid to vapor.
  • Thus, evaporating water is a great way for
    organisms to shed excess heat.
  • Many animals pant or sweat to moisten evaporative
    cooling surfaces.

9
High Specific Heat
  • Water absorbs a great deal of heat before it
    changes temperature.
  • The slow response of water to temperature change
    helps moderate global temperatures, keeping the
    environment warm in the winter and cool in the
    summer.
  • This effect is especially noticeable near the
    ocean, but is important globally.

10
aqua
  • All of these properties make water a unique and
    vitally important component of the ecological
    cycles that move materials and energy and make
    life on earth possible.
  • Adapted from pg. 29 in Principles of
    Environmental Science by William P. and Mary Ann
    Cunningham

11
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