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Convection

The transfer of heat by motions in a liquid or gas.

The most familiar example is boiling water.


http://science.nasa.gov/ppod/y2003/01may_boiling.htm http://science.nasa.gov/headlines/y2001/ast07sep_2.htm http://www.phys.unsw.edu.au/~jw/superheating.html This phrase geologic time is often used in the same way people refer to part of a lifetime, suggesting an unspecific span of time on the order of tens of years less than seventy years. For example - "Over geologic time, entire mountain ranges such as the Appalachians that were once as tall as the Rockies, have been eroded into hills.

Note: Definitions are a work in progress.

Convection

  1. The transfer of heat by motions in a liquid or gas.


    What is heat?
    "Heat is energy that flows between a system and its environment by virtue of a temprature difference that exists between them."
    - Halliday and Resnick, Convection is one of the three ways, covection, conduction and radiation in which energy can be transfered between a system and its environment. In convection, the matter that possesses the energy moves. In conduction, matter is transmitted from adjacent matter, but the matter itself doesn't move. In radiation, matter doesn't move and energy is transmitted without the need for intervening matter.

    Convection is a core physical process. *Things move in response to differences in temperature, gravity, pressure
    This topic applies to:
    The motion of rock within the Earth. The motion of seawater The motion of air Boiling water

Other definitions - Convection Note differences

  1. "TBA."
    From adopted textbook.
  2. "transfer of heat within a liquid or gas"
    Glossay, Concepts and Challenges: Earth Science Fourth Edition, Globe Fearon, 2003.
  3. "The theory that the Earth's lithosphere consists of large, rigid plates that move horizontally in response to the flow of the asthenosphere beneath them, and that interactions among the plates at their borders cause most major geologic activity, including the creation of oceans, continents, mountains, volcanoes, and earthquakes."
    Houghton Mifflin College Division Online Study Center

How scientists get ideas

  1. "Movements of the Earth's crustal plates, which result in changes in the position, size, and shape of continents and oceans."
    Edward O. Wilson, ...

Questions for thought

  1. Is the Earth significantly younger than the Sun?
  2. Are the planets significantly different in age?
  3. The end of the Cretaceous, 65 million years ago, marked by the K-T asteroid impact marked the end of the Age of Reptiles and beginning of Age of Mammals. If the entire duration of the Earth's history were compressed into a week, on what day and what hour did the Tertiary begin?
  4. When do fossils of early humans appear in the rock record?
  5. What is the average lifespan of people today?
  6. How many generations of people can you identify in your own family?
  7. How many generations of people would have passed through even 1,000 years?

Engagement

  1. To see and compare several definitions of any word that interests you -
    Type "define plate tectonics" in a Google search

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