Matter, energy. Measurement of Matter.

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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 0^ø 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 4^ø 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.