Encyclopedia of Earth and Physical Sciences - Vol. 7

By Joyce Tavolacci | Go to book overview

MATERIALS SCIENCE
The study, development, and
application of materials in
industry and everyday life

Stone was one of the first
materials to be used to
make things, such as
Stonehenge in England

CONNECTIONS
PLASTICS are
POLYMERS made
from CARBON-based
MOLECULES.
SYNTHETIC
FIBERS
have
revolutionized the
design of clothing
and textiles.

From the Stone Age to the age of computers, nuclear power, and genetic engineering, materials science has always played a fundamental role in the history of technology. Prehistoric cave dwellers who fashioned tools from stone and bone were the materials scientists of their day: they discovered materials, learned about their properties, and applied those materials to problems in their everyday lives. Today, materials scientists do much the same thing, with one added dimension. Using a detailed knowledge of atomic and molecular structure, they can design and build entirely new materials that have never previously existed.


Properties of materials

Materials scientists concentrate on those properties of materials that make them good or bad for a particular purpose. Thus, the hardness or softness of a material (which can be measured using Mohs’ scale; see MOHS’ SCAL E), its melting point (whether it is a solid, liquid, or gas at room temperature), how well it conducts heat and electricity, how well it stands up to constant use, and how heavy or light it is are all important considerations (see HEAT; MEETING AND BOILING POINTS; THERMODYNAMICS). Materials are distinguished both by their chemical properties, how they behave in the presence of other substances, such as whether they dissolve in water or react with acids, and physical properties, how they behave in their own right; for example, how they reflect light (see CHEMISTRY; RE FLECTION AND REFRACTION).

When materials are used in engineering structures or the moving parts of machines, their mechanical properties, the way they withstand forces of different kinds, are especially important. Some materials are brittle; others are elastic—they return to their original shape after being stretched or squeezed—or plastic—they deform out of shape when a force is applied. Different materials behave in quite different ways under tension (when stretched) and compression (when squeezed). Some materials may appear to withstand large forces very well but gradually deform over time, a phenomenon known as creep, or fracture after being subjected to regular stresses and strains, a related problem called fatigue. Materials scientists need to understand not just the properties of materials when they are new but how they will behave over their entire lifetime.


Types of materials

Materials with a similar chemical makeup or similar physical properties can be grouped together in different categories. Semiconductors generally have a similar chemical makeup, being based on such elements as silicon and germanium and similar physical properties—they conduct electricity easily only when atoms of impurities are added to them (see SEMICONDUCTORS). By placing different impurities in adjacent regions of a semiconductor, the result is a structure that allows a current to flow in one direction, which can be manipulated by an electrical signal, leading to a wide range of applications.

Materials can also be classified according to how they are used. People commonly talk of such metals as aluminum and titanium as aerospace materials.

CORE FACTS
Materials are chosen for a particular purpose according
to their physical and chemical properties.
Composites (combinations of two or more materials) are
among the most advanced materials in use today.
Materials science has played a vital part in the advance
of such fields as microelectronics, biotechnology, and
medicine.

-888-

Notes for this page

Add a new note
If you are trying to select text to create highlights or citations, remember that you must now click or tap on the first word, and then click or tap on the last word.
One moment ...
Default project is now your active project.
Project items
Notes
Cite this page

Cited page

Style
Citations are available only to our active members.
Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

(Einhorn, 1992, p. 25)

(Einhorn 25)

(Einhorn 25)

1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

Note: primary sources have slightly different requirements for citation. Please see these guidelines for more information.

Cited page

Bookmark this page
Encyclopedia of Earth and Physical Sciences - Vol. 7
Table of contents

Table of contents

Settings

Settings

Typeface
Text size Smaller Larger Reset View mode
Search within

Search within this book

Look up

Look up a word

  • Dictionary
  • Thesaurus
Please submit a word or phrase above.
Print this page

Print this page

Why can't I print more than one page at a time?

Help
Full screen
Items saved from this book
  • Bookmarks
  • Highlights & Notes
  • Citations
/ 1008

matching results for page

    Questia reader help

    How to highlight and cite specific passages

    1. Click or tap the first word you want to select.
    2. Click or tap the last word you want to select, and you’ll see everything in between get selected.
    3. You’ll then get a menu of options like creating a highlight or a citation from that passage of text.

    OK, got it!

    Cited passage

    Style
    Citations are available only to our active members.
    Buy instant access to cite pages or passages in MLA 8, MLA 7, APA and Chicago citation styles.

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn, 1992, p. 25).

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences." (Einhorn 25)

    "Portraying himself as an honest, ordinary person helped Lincoln identify with his audiences."1

    1. Lois J. Einhorn, Abraham Lincoln, the Orator: Penetrating the Lincoln Legend (Westport, CT: Greenwood Press, 1992), 25, http://www.questia.com/read/27419298.

    Cited passage

    Thanks for trying Questia!

    Please continue trying out our research tools, but please note, full functionality is available only to our active members.

    Your work will be lost once you leave this Web page.

    Buy instant access to save your work.

    Already a member? Log in now.

    Search by... Author
    Show... All Results Primary Sources Peer-reviewed

    Oops!

    An unknown error has occurred. Please click the button below to reload the page. If the problem persists, please try again in a little while.