# Particle Theory Of Matter by liaoqinmei

VIEWS: 20 PAGES: 8

• pg 1
```									PARTICLE THEORY OF MATTER
Theories and Models

 Scientists use theories and models to try to
explain why things work the way they do.
 A “good” theory can be used to predict
certain events in the system
 If the theory constantly predicts the behavior
of a system and what happens, then it is
accepted as accurate
Particle Theory

 This is a model we use to try to explain how
matter behaves
 This theory is over 100 years old
 Remember that matter is the “stuff” that
makes up a substance
Particle Theory Cont

 The basic units of matter are atoms and
molecules
 Atoms
 the smallest particle of an element that can exist
either alone or in combination
 Molecules
 the smallest particle of a substance that retains all
the properties of the substance and is composed
of one or more atoms
What the Theory Says
   All Matter is made up of small particles.
These particles are so small that literally billions of them fit on this dot "."
   All particles of a pure substance are identical. For example ice, water and water
vapour are all made of H20 and each particle (molecule) of each (ice, water ...)
have the exact same MASS and VOLUME.
   The particles in matter are "attracted" to each other. This attraction becomes
stronger as the particles get closer to each other ! This explains why solids are
more rigid than liquids (Solids are usually denser than liquids).
   The spaces between the particles are HUGE compared to the size of the actual
particles.
   The particles in matter are ALWAYS IN MOTION. The speed of the particles
depends on the temperature. When particles are HOT they have MORE energy
and are moving faster than cold particles. The motion of particles causes them to
bump around and bounce off each other.
Solids

 In Solids the particles
are moving slow (they
vibrate) and the
particles in the solid do
NOT have enough
energy to overcome
the attractive forces
between them.
 We call this a lattice
structure
Liquids

 In Liquids the particles
are moving fast
enough to move
around each other but
they do NOT have
enough energy to
overcome the
attractive forces
between them
Gases

 In Gases, the particles
are moving so fast that
they have enough
energy to overcome
the attractive forces
between them

```
To top