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Matter, energy. Measurement of Matter.
MATTER AND ENERGY
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
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.
Physical Change. In a physical change the composition of the molecules of
the substance is not changed. Examples: water freezing, dissolving sugar
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. The ability to do work. Examples: Heat, light, electrical
Physics. The science which deals with matter and energy and the physical
changes in matter.
Major divisions of physics.
6. Nuclear physics
THE PROPERTIES OF MATTER.
General properties of matter.
- occupies space (has volume)
- has mass (weight)
Three phases of matter
Solid. The phase of matter which has a definite shape and a definite
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
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
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
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
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
Gram. One cubic centimeter of distilled water at 4ø C has a mass of one
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.
Dull, Metcalfe, Brooks. Modern Physics.
Freeman. Physics made Simple.