Physics 7450: Solid State Physics 2 Lecture 2: Elasticity ...
ELASTICITY AND FLUID PHYSICS
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Transcript of ELASTICITY AND FLUID PHYSICS
ELASTICITY AND FLUID PHYSICS
Reporters:Ace B. Correos
Gerone P. RicardoJethru Ray A. Canoy
Demie Xyza F. Rendon
Is a substance of which all objects
are made. An object’s resistance to a change
in its state of motion.
A Review of Matter
Mass is a measure of inertia. Is a source of gravitation
Weight is the term used in science and technology for the gravitational force between planet or any other large object and relatively small objects.
Matter can be changed into energy and energy into matter.
A Review of Matter
Matter has structure at many levels,
from groupings of galaxies so vast that light rays take hundreds of million years to cross them to particles so small that scientists describe them as point-like.
Structure of Matter
An atom is made up of particles called
protons, electrons and neutrons.
Proton- a positively charged elementary particle that is a
fundamental constituent of all atomic nuclei.
- it is the lightest baryon
Structure of Matter
Neutron- an elementary particle having no charge.
- its mass is slightly greater than that of a proton Electron- an elementary particle that is a
fundamental constituent of matter
-it is the component outside the nucleus of an atom.
Structure of Matter
Protons and neutrons, which carry most of the
atom’s mass, are composed of point like units known as quarks.
Particles smaller than an atom is called subatomic particles.
The diameter of an atom ranges from about 0.1 to
0.5 nanometre.
Nanometre- is a billionth of a meter or is
Structure of Matter
The General States of Matter
Matter can change from one state to another.
Solids tend to retain their shape, and they resist
compression (reduction in the amount of space they occupy)
Liquids assume the shape their container and can flow freely. Like solids they also resist compression. The atoms or molecules of a liquid are in contact with one another but are not linked, so they can move freely.
The General States of Matter
Gases expand to fill their containers,
and the can be compressed fairly easily. The atoms or molecules of a gas are not in contact with one another and are always moving violently.
The General States of Matter
Plasma Superconductor Superfluid Bose-Einstein condensate
The Physicists’ Other States of Matter
Plasma are gas-like substances in which some
or all atoms have lost at least on electron, leaving a mixture of free electrons and positively charged ions. Plasmas form at temperatures of tens of thousands of degrees or higher, or through the action of an electric current. On earth, plasmas are found in lightning discharges and in fluorescent lights and neon signs.
The Physicists’ Other States of Matter
Superfluids are fluids that low without
resistance. As a result, they will pass through the pores of a container. Scientists have found this phase only in helium, one of the few substances that remain a liquid within a few degrees of absolute zero: -
459.67 ˚F or -273.15 ˚C. At absolute zero , atoms and molecules would have the least possible energy.
The Physicists’ Other States of Matter
Superconductors are solids in which electrons move
freely. Once started, am electric current in a superconductor can flow forever without the help of an external power supply. Many metals are superconductors at temperature within few degrees of absolute zero. Others exhibit superconductive properties at temperatures more than 100 degrees or -173.16 ˚C above absolute zero.
The Physicists’ Other States of Matter
Bose-Einstein Condensates, also known as BEC’s,
are clusters of millions of atoms that merge under conditions of extreme cold. BEC’s can form in some gases when they are cooled to within a few billionth of a Celsius degree of absolute zero. When a BEC forms, million of atoms stop moving in different directions at different speeds ad instead act as a single atom.
The Physicists’ Other States of Matter
The Condensates are named after
physicists Satyendranath Bose of India and Albert Einstein of Germany who proposed the possibility of BEC’s in the 1920’s
The Physicists’ Other States of Matter
Scientists have discovered an unusual
form of matter called antimatter. Dark matter which may be fundamentally different from ordinary matter, apparently also exist. Physicists do not know what it is made of, however.
Unusual Forms of Matter
Antimatter
Physicists can convert energy into matter with devices called particle accelerators. When subatomic particles collide at high speeds, they create new particles. Whenever particles of matter are created, an equal number of particles of antimatter are also made. Antimatter particles are equal in mass to the equivalent particles of matter but opposite in electric charge and certain other properties.
Unusual Forms of Matter
-For example, positrons, which are
positively charged, are the antimatter equivalent of electrons. If a matter particle meets an equivalent antimatter particle, the two particles destroy each other. Both particles are converted into energy.
Unusual Forms of Matter
Antimatter particles are rare and last only until
they encounter matter and are destroyed. there appear to be no large concentrations of antimatter anywhere in the universe. On Earth, they are mainly a laboratory curiosity. Medical technology, however, makes use of positrons in a technique called positron
emission tomography (PET). PET images reveal the chemical activity of areas of the brain and other body tissues.
Unusual Forms of Matter
Dark Matter
More than 99% of the visible universe is made up of the two lightest kinds of atoms, helium and hydrogen. It appears, however, that most of the matter in the universe is invisible dark matter. Scientists have detected dark matter only through the influence of its gravitational force on the motions of visible matter. Many scientists believe that dark matter is composed of undiscovered particles.
Unusual Forms of Matter
Density- is the mass – that is, the
amount of matter – in a unit volume of any substance.
Mathematically, D=
Where:D= Density
Density and Specific Gravity
M= Mass V= Volume
Earth scientists use density
measurements to identify minerals and other solids. Chemists measure the density of a solution to determine the concentration of a substance in that solution. They also calculate the molecular weight of a gas from its density.
Density and Specific Gravity
To measure the density of a regular
shaped solid, first measure the object’s mass – that is, weigh the object. Next, measure one or more of the object’s dimensions and calculate its volume from a mathematical formula for objects of that shape. Then divide the mass by the volume.
Density in Solids
It is more difficult to find the density of an
irregularly shaped solid because the volume is harder to determine. To determine the volume, submerge the object, then measure the volume of the water displaced. This volume equals the volume of the object.
Density in Solids
The density of gas is difficult to measure
because gases have low densities and the density of gases changes greatly with variations in temperature and pressure. To determine the mass of a gas, first weigh an empty container. Next, fill the container with the gas and weight it again.
Density in Gases
Then subtract the first
measurement from the second. To determine the volume of the container, measure the amount of water that the container holds.
Density in Gases
The specific gravity of a substance is related
to its density. Specific gravity equals the mass of a given volume of the substance divided by the mass of an equal volume of water. To determine the specific gravity of a substance, divide the density of the substance by the density of water at either 4 ˚C (39 ˚F) or 20 ˚C (68 ˚F).
Specific Gravity