All substances are made of matter. Everything in the universe is either matter or energy

Definition of matter- Anything that takes up space and has mass.

               Particle Theory of Matter

          -  All matter is made of tiny particles. 

          -  These particles are always moving ( vibrating). ( the faster the particles, the
              more energy they have)
         -   There is space between each particle. 

         -   The particles are attracted to one another.

        -   The particles in one substance are different from the particles in another substance.

Kinetic Energy

The kinetic energy of a substance is the energy it has due to motion.

- The faster an object- the                     
  more kinetic energy.


-The larger the mass of a
  moving object, the more
  kinetic energy it has.


Kinetic Energy and Temperature

All matter is composed of particles that are moving. This means these particles have kinetic energy. These particles move faster when they are heated.

Therefore we can define temperature
of a substance as: The average kinetic energy of it's particles.

           - The faster the particles move- the higher the kinetic energy- the higher
the temperature. Some examples are: when we rub our hands together, we make the particles in our hands move faster, and our hands warm up. Also when we shoot microwaves at food we make the particles in the food vibrate faster, which makes the food hotter.

States of Matter

All matter takes the form of either solid, liquid, or gas. Water is the only substance on Earth that is present in all three forms at the same time. 



Solids have a fixed shape and a volume that does not change. 

            -    The reason for this has to do with the particles.The particles
                  in a solid are packed closely together. There is a strong attraction between the                              particles which cause them to stay close together. They vibrate in place but do not                      move around. 




Liquids take the shape of the container but have a volume that does not change. The
particles in a liquid are packed closely together but are less attracted to each other than in
a solid. This means they can slide past each other and move slightly around.



Gas takes the shape of the container and the volume of the container. The particles in
a gas are not close together and have little attraction for each other. The particles
collide with each other and move around.

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Thermal Expansion - When an object is heated, it's volume increases ( it gets bigger).

Thermal Contraction - When an object is cooled down, it's volume decreases( it gets smaller).

Some examples:       

ball and ring apparatus (demonstration).

Train tracks/bridges have expansion gaps so they don't bend/collapse in the summer.

A balloon gets smaller when placed outside on a cold day.

liquid in a thermometer.

Telephone wires expand and sag in summer.

Expansion/Contraction/Particle Theory

Question: Why does matter expand when heated and contract when cooled?

Answer: When matter is heated, the particles move more quickly. When they  collide with each other,because they are moving faster, they have more force and bounce farther apart. When the particles move farther apart, the objects gets bigger- it expands.



Changes of State

There are three states of matter- solids, liquids, and ?gases. When a substance changes from any of these ?states to another state, it is called a Change Of State. 

 Change of State                 Name                             Example

solid to a liquid                 melting                   ice cubes melts

solid to a gas                    sublimation                 urinal cake

liquid to a gas                   evaporation                     sweating

liquid to a solid                 freezing                        water to ice

gas to a solid                     deposition                          hail

gas to a liquid                 condensation                        rain