Transcript Elasticity - saira arif

Matter is anything that has mass and
takes up space.
How It Looks (Shiny ,Dull, Color, etc.)
 How It Feels (Hard, Soft, Rough , Smooth, etc.)
 How It Smells (Sweet, Sharp, Terrible, No Smell,
etc.)
 How It Sounds (Loud, Soft, Echo, No Sound, etc.)
 What It Does (Bounce, Stretch, Tear, Break,
Magnetism etc.)


A solid is matter that has that has definite size
and shape.

Particles of solids are tightly packed, vibrating
about a fixed position.

Solids have a definite shape and a definite
volume.

A liquid takes the shape of any container.

Particles of liquids are tightly packed, but are
far enough apart to slide over one another.

Liquids have an indefinite shape and a definite
volume.

Gas is matter that has no definite shape. Gases
take the shape of whatever container they are in.

Particles of gases are very far apart and move
freely.

Gases have an indefinite shape and an
indefinite volume.
Description of
Phase Change
Solid to
liquid
Liquid to
solid
Term for Phase
Change
Heat Movement During
Phase Change
Melting
Heat goes into the
solid as it melts.
Freezing
Heat leaves the
liquid as it freezes.
BUT WHAT HAPPENS IF YOU RAISE THE
TEMPERATURE TO SUPER-HIGH LEVELS…
BETWEEN
1000°C AND 1,000,000,000°C ?
Will everything
just be a gas?

A plasma is an ionized gas.

A plasma is a very good conductor of electricity and
is affected by magnetic fields.

Plasmas, like gases have an indefinite shape and an
indefinite volume.
SOLID
Tightly packed, in
a regular pattern
Vibrate, but do
not move from
place to place
LIQUID
Close together
with no regular
arrangement.
Vibrate, move
about, and slide
past each other
GAS
Well separated
with no regular
arrangement.
Vibrate and move
freely at high
speeds
PLASMA
Has no definite
volume or shape
and is composed
of electrical
charged particles
Flames
2.
Lightning
The Sun is an example of a
star in its plasma state
 Pressure
is equal to the force applied
to a surface, divided by the area.
Pressure = Force/surface area
•Units are in pascal (Pa) or N/m²

Stress is the force that produces strain on a
physical body without undergoing some sort of
physical change.
Stress = σ = F/A

UNIT: N/m2 or Pascal
Strain is the deformation of a physical body under the
action of applied forces
The tendency of a body to return to its original
shape after it has been stretched or compressed
The physical property of being stiff and resisting
bending
Stress and strain are directly proportional to
each other. The constant of proportionality is
called a modulus of elasticity, so that
Stress = Elastic modulus × Strain
We consider three types of deformation and define an
elastic modulus for each:
1. Young’s modulus
2. Shear modulus
3. Bulk modulus
Young’s modulus or Elasticity in Length
It measures the resistance of a solid to a
change in its length.
Shear modulus or Elasticity of Shape
It measures the resistance to motion of the planes
within a solid parallel to each other.
Bulk modulus or Volume Elasticity
It measures the resistance of solids or liquids to
changes in their volume.

In fact metals are altered by most of their experiences if they are
exposed to stress for a long time then repeated deformation of
metals causes them to crack and break. This cracking process is
called fatigue .

fatigue is the progressive and localized structural damage that
occurs when a material is subjected to cyclic loading.




This type of deformation is irreversible.
A break occurs after the material has reached the end
of the elastic, and then plastic, deformation ranges.
At this point forces accumulate until they are sufficient
to cause a fracture.
All materials will eventually fracture, if sufficient forces
are applied.