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Matter, energy. Measurement of Matter.



 MATTER AND ENERGY



MATTER.


  Matter. Anything which occupies space and has weight. Examples: Solids

    such as wood, iron, copper, gold, and salt; Liquids such as water,

    alcohol, gasoline and turpentine; Gases such as oxygen or acetylene.


  Composition of Matter. Chemists have found that all complex substances

    --- wood, steel, glass, plastics, even the waters of the ocean and the

    air we breathe --- are mixtures of chemical compounds. Nearly a million

    compounds have been identified, and these, in turn, are merely different

    combinations of only about a hundred chemical elements known to science.

    A compound is a substance consisting of a particular type of molecule.

    A molecule consists of two or more atoms that are chemically bonded

    together. Atoms are composed of neutrons, protons and electrons. There

    are around a hundred kinds of atoms corresponding to the different

    chemical elements.


    Molecule. The smallest particle into which matter may be divided without

      destroying its characteristic properties. It is a particle of matter

      consisting of one or more atoms chemically bonded together.


    Atom. The smallest particle of a chemical element.



  Three Types of Changes in Matter.

    1. Physical

    2. Chemical

    3. Nuclear


  Physical Change. In a physical change the composition of the molecules of

    the substance is not changed. Examples: water freezing, dissolving sugar

    in water.

  Chemical Change. In a chemical change the composition of the molecules of

    the substance is changed, and new substances with new properties are

    produced. Example: Iron rusting to produce iron oxide.

  Nuclear Change. In a nuclear change new materials are formed by changes

    in the identity of the atoms themselves. Example: gradual change of

    radium atoms into lead atoms.

   



ENERGY.


  Energy. The ability to do work. Examples: Heat, light, electrical

  waves.




PHYSICS.


  Physics. The science which deals with matter and energy and the physical

    changes in matter.


  Major divisions of physics.

    1. Mechanics

    2. Heat

    3. Sound

    4. Light

    5. Electricity

    6. Nuclear physics






THE PROPERTIES OF MATTER.


  General properties of matter.

     - occupies space (has volume)

     - has mass (weight)

     - impenetrability

     - porosity


  Three phases of matter

    1. solid

    2. liquid

    3. gaseous


  Solid. The phase of matter which has a definite shape and a definite

    volume.

  Liquid. The phase of matter which has a definite volume but takes the

    shape of its container.

  Gas. The phase of matter which has neither a definite shape nor a

    definite volume. Unlike solids and liquids gases have no surfaces or

    boundaries.


    Gases not only take the shape of their container, they also expand and

      fill it up, no matter what its volume.

 

  Fluid. A liquid or gas.


  Viscosity of a fluid. The ease with which a fluid flows. A liquid, such

    as water, that flows easily has a small viscosity. A substance, such as

    tar, which flows slowly has a much larger viscosity.


    In general, an increase in temperature decreases the viscosity of a

      fluid.


  Mass. The measure of the quantity of matter. The weight of a body can

    vary depending on where it is weighed (i.e. at sea level, on top of a

    mountain, or on the moon) but its mass does not vary.


  Weight. The measure of the earth's attraction for a body.


  Impenetrability of matter. The property of matter by virtue of which two

    objects cannot occupy the same space at the same time.


  Porosity of matter. The property of having small openings or spaces

    between the particles.



 


THE MEASUREMENT OF MATTER


  Systems of Measurement

    English system

    Metric system


  English system.

    Units of length: inches, feet, yards, miles

    Units of area: square feet, square yards

    Units of volume: cubic inches, cubic yards, quarts, gallons

    Units of weight: ounces, pounds, tons

    Units of time: second


  Metric system. In the metric system the meter is the unit of length; the

    liter is the unit of volume; and the gram is the unit of mass. The

    common subdivisions of each of these units are formed by the use of the

    prefixes centi-, 1/100; and milli, 1/1000. The most common multiple of

    each of the units in the metric system is formed by using the prefix

    kilo-, 1000.


    Units of length: meter, centimeter, millimeter

    Units of area: square meters, square centimeters

    Units of volume: cubic meters, cubic centimeters, liters

    Units of weight: grams, kilograms

    Units of time: second


    Standard meter. The distance , measured at 0ø C, between two parallel

      lines scratched on a platinum-iridiun bar kept at the International

      Bureau of Weights and Measures at Sevres, near Paris, France.


    Liter. A liter is the volume of a cubical box that measures 10

      centimeters on each side. It is equivalent to 1000 cubic

      centimeters.

    

    Gram. One cubic centimeter of distilled water at 4ø C has a mass of one

      gram.



  Three systems of measurement used in physics.

    Foot-Pound-Second, or FPS system

    Meter-Kilogram-Second, or MKS system

    Centimeter-Gram-Second, or CGS system




  Density of a Substance. The density of a substance is its weight per unit

    volume and is given by the formula D = w/V where D is the density, w is

    the weight and V is the volume.





References

 Dull, Metcalfe, Brooks. Modern Physics.

 Freeman. Physics made Simple.


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