© 2004 NSF/STARS. All rights reserved. GK-12 NSF STARS

GK-12 NSF STARS

© 2004 NSF/STARS. All rights reserved.

GK-12 NSF STARS


Wonders of a Small Small Small World

Presented by:

Souheil Zekri


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Sunshine Standards and GLE’sStandard 2: The student understands the basic principles

of atomic theory. Benchmark SC.A.2.2.1: The student knows that materials may be made of

parts too small to be seen without magnification.

Grade Level ExpectationsThe student:

Third 1. uses a tool to observe and study minute details of objects (for example, hand

lens). Fourth 1. uses a variety of tools (hand lens, microscope) to observe and study minute

details of objects. Fifth 1. knows that materials may be made of parts too small to be seen without

magnification.

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Lesson Layout

Classification of Materials

History of Materials

Atoms and Molecules and Nanotechnology

Microscopes

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Classification of Materials

Metals and AlloysCeramics, glasses, and glass-

ceramicsPolymersSemiconductorsComposite materials

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Metals and Alloys Metals are ductile (easily formable),

strong, good conductors of heat and electricity:– Aluminum, Chromium, Nickel,

Copper, Iron, Titanium, etc… Alloys are combinations of metals made

to improve the physical properties of certain metals metal such as:– Bronze (combination of copper and

tin)– Brass (copper and zinc)– Steel (Iron, Carbon, Manganese,

Tungsten, Chromium, Nickel, Cobalt…)

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Ceramics and Glasses Ceramics and Glasses are

brittle (brake easily on impact), hard, bad heat and electric conductors (usually used as insulators):– Quartz (SiO2)

– Titanium carbide (Titanium mixed with carbon elements).

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Polymers Polymers (poly means many) are

divided into plastics and elastomers:

– Plastic (when deformed they don’t return back to its original shape): group of synthetic materials processed by heating and forming or molding into shape (ex: Nylon)

– Elastomers (natural rubber): is elastic (could stretch and get back to its original shape)

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Semiconductors

Semiconductors are used in electronics (game boy, XBOX, PS2, computers…).

Semiconductors can act as conductors and insulators at the same time.

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Composite Materials

Composites are formed from two or more different materials that could be metal, ceramic, or polymer (ex: fiberglass, concrete, etc…)

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History of Materials: a time line

Adapted from: http://people.clarityconnect.com/webpages/terri/history.html

Matter divided into water, earth, air fire

Idea of the atom is born

Alchemy is born

Periodic table Modern atomic theory

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Early classification of Matter

The Greek Empedocles of Agrigente divided matter into 4 elements and calls them roots around 492-432 BC:– Water– Earth– Air – Fire

Aristotle thought that all matter using ratios of the four basic elements.

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Early concept of atoms

Leucippe of Milet invents the notion of atom or "a-tomos" in Greek, which signifies "indivisible". in 420 before J.C

His disciple, Democritus of Abdere (around 460-370 BC.), explained that matter was made up of particles in perpetual motion.

http://perso.club-internet.fr/molaire1/e_histoire.html

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The Alchemy of the middle ages

During the 8th and 9th century Jabir ibn Hayyan and ibn Sina developed many of the concepts of Al-kemia arabic for Alchemy, which marks the birth of Chemistry and Pharmacy.

Medieval European scientists used their principles to develop further understanding of matter and its composition.

Select an element from the periodic table.

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Mendeleev’s first periodic table

In 1869 Dmitri I. Mendeleev published the first periodic table that organized elements in groups with similar characteristics.

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Modern periodic table periodic table

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The Atom: Bohr’s atomic model

Proton

Neutron

Electron

Hydrogen Atom

Nucleus

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Today’s atomic model

Region where electron has less probability to exist

Region where electron will most probably be

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What is Air Made Out of?

78%

21%

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Water Molecule

A molecule is the simplest unit of a chemical compound that can exist, consisting of two or more atoms held together by chemical bonds

A water molecule consists of one oxygen atom and two hydrogen atoms

Picture courtesy of http://www.lsbu.ac.uk/water/molecule.html

105o

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What is a Nanometer

3 ft = 1 meter1meter = 1000 millimeter1 millimeter = 1000 micrometer 1 micrometer = 1000 nanometer

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Entering the Nanoworld

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How Would a Nanometer Compare to Human Hair?

~ 1 nanometer

Human hair magnified 1000 times: courtesy of http://acept.la.asu.edu/PiN/rdg/elmicr/optical.shtml

100,000 nanometers

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Atomic GeometryOne Proton (or Neutron) weighs about 1,835 times larger than an electron!!!Most of the atom is empty with a very dense nucleusThe nucleus is so dense that if we took only nuclei and packed them into a ½ inch cube, the cube would weigh 133,000,000 tons! If we increase the nucleus to the size of a pea, the electron would be about ½ a mile a way from it.

9.10 x 10-28 grams 3 x 10-24 grams

5 x 10-11 m = 0.05 nanometer

1 x 10-18 m = 0.000000005 nanometer

5 x 10-15 m = 0.000005 nanometer

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So What do we Use to See an Atom?

Certainly not light microscopes! We use Electron microscopes.

Picture of a moth wing magnified 15,000 times

courtesy ofhttp://www.mos.org/sln/sem/moth.html

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Pictures of atoms

Quantum corral of Iron on Copper (111) (Physics Today 46 (11), 17-19 (1993).

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Nanotechnology

Science and technology applied to the nanoscale, which varies from 100 nanometers to 1 nanometer.

Make faster and smaller computersHelp medicine by making small nanorobots

that travel through blood stream

Documents

© 2004 NSF/STARS. All rights reserved. GK-12 NSF STARS