Substances exist as either solids, liquids or gases. But what makes them different?

It has to do with the arrangement and motion of the particles that make up the substance.

An explanation of how particles in matter behave is called the

Kinetic Theory, which states that all matter is made up of small particles, which are in motion.

THERMAL ENERGY

This is the total amount of energy in a substance.

Thermal energy will decrease as temperature decreases.

When thermal energy decreases, the particles in a substance vibrate and move more slowly.

Think about it….why is water in the form of ice (a solid) at low temperatures?

TEMPERATURE

Temperature is defined as the average kinetic energy in a substance, or how fast these particles are moving.

For example, water molecules at 0 degrees Celsius have less kinetic energy than those at 100 degrees Celsius.

What is absolute zero? It is the temperature at which molecules move so slowly that no more thermal energy can be removed. In degrees Celsius, this is -273.

SO WHAT IS A SOLID?

Well, a solid is quite literally something that you can’t easily put your hand through, right? It has a definite shape due to the fact that the particles it is made up of are closely packed, moving very little and have a set geometric arrangement.

NOW, WHEN YOU ADD THERMAL ENERGY TO A SOLID…

You reach the melting point. This is the temperature at which a solid starts to turn in to a liquid. The particles will move more and move apart. This changes everything. This extra energy allows particles to slide past each other, allowing liquids to flow and take the shape of their container.

SO HOW IS A GAS DIFFERENT?

You can probably figure this out yourself since there is a pattern here…

You guessed it! Just add more thermal energy, causing the molecules to move even faster and farther apart. This causes the particles to spread out so much that gases don’t even have a set volume or shape.

Liquids can become gases in two ways:

1. Evaporation

2. Boiling

EVAPORATION

BOILING

Heat of Vaporization - This is the amount of energy needed for a liquid at its boiling point to become a gas.

Diffusion – the spreading of particles throughout a given volume until they are evenly distributed; this happens fastest in gases

HEATING CURVE OF A LIQUID

PLASMA

Okay, so not everything follows the rules….

Plasma is a state of matter found in extremely HOT places, like the Sun. It contains very high energy particles.

BEHAVIOR OF GASES

The behavior of gases is not measure in the same way your behavior is…they don’t have moods, or act out.

However, they do change in relation to temperature and pressure.

Pressure – how much force is exerted over an area; measured in units called Pascals

BOYLE’S LAW

IN OTHER WORDS…

IN GRAPH FORM…

CHARLES’S LAW

AS A FORMULA…

AS A GRAPH…