Four Phases of Matter and Phase Changes: class blog 2

Remember how all objects have matter? Well, now we will get more into the phases of matter and the phase changes. There are four main stages of matter: solid, liquid, gas, and plasma. Solids have a definite shape and volume. The particles of a solid cannot move far out of place because they are packed close together. Liquids have a definite volume but not a definite shape. The particles are close together but are free to move. Some liquids are more dense than others so they have more viscosity, the resistance of a liquid to flow. Gases have no definite shape or volume. The particles are spread out and are not arranged in a pattern, so they can move around freely. Plasma, the most rare phase on Earth, but the most common in the universe, cannot be contained by the walls of a container. In addition, plasma is high in energy, so it is dangerous to living things.

EXAMPLES:
solid- pencil
liquid- water
gas- oxygen
plasma- sun

Now that we have discussed the four phases of matter, we will talk about the phases changes of solids, liquids, and gases.

Solid-Liquid Phase Changes: The phase change of a solid to a liquid is called melting. When an object absorbs heat energy, it melts. The temperature at which it melts is called the melting point. Most objects have a specific melting point. For example, the melting point of ice is 0℃ whereas that of a diamond is 3700℃. The phase change of a liquid to a solid is called freezing. When an object loses heat energy, it freezes. The temperature at which it freezes is called the freezing point. Like melting, most objects have a specific freezing point. Just like ice melts at 0℃, water freezes at 0℃. This is because the freezing point of an object is equal to it’s melting point.

Liquid-Gas Phase Changes: The phase change of a liquid to a gas is called vaporization. Vaporization is when the particles of a liquid have absorbed a certain amount of heat energy in order to become a gas. If vaporization occurs at the surface of the liquid, evaporation has occurred. However, not always does vaporization occur at the surface of the liquid. When a liquid is given enough heat energy, the particles inside a liquid and the particles at the surface of the liquid change into a gas. This process is called boiling. Most liquids have a boiling point. Water usually boils at 100℃. The boiling point depends on the air pressure: the higher the air pressure, the higher the boiling point. The phase change of a gas to a liquid is called condensation. When a liquid loses vapor (heat energy), the vapor becomes a liquid.

Solid-Gas Phase Changes: The phase change of a solid to a gas, without undergoing the liquid phase, is called sublimation. This means that the particles of a solid escape right into the gas phase. For instance, dry ice is frozen (solid) carbon dioxide. When dry ice absorbs heat energy, it automatically becomes a gas. The phase change of a gas to a solid is called deposition.

In my opinion, all this information about matter is intriguing because one never really realizes that all these phase changes are, well, phase changes. They just think it is a work of nature. I enjoyed learning about phase changes other than evaporation.

Some interesting facts:
1. To elaborate on deposition, snow is an example. Snow is vapor that changes directly into ice in the clouds. When it becomes ice, it falls to the ground.
SOURCE: Wikipedia
hyperlink: http://en.wikipedia.org/wiki/Deposition_%28physics%29

2. Phase changes occurs by increasing or decreasing energy. When a certain temperature is reached, phases change. Air pressure is also a factor in phase changes.
Liquid+Energy=Gas
Gas-Energy=Liquid
Solid+Energy=Liquid
Liquid-Energy=Solid
Solid+HIGH Energy=Gas
Gas-HIGH Energy=Solid
SOURCE: Rader's Chem4Kids
hyperlink: http://www.chem4kids.com/files/matter_changes.html

PICTURE from: (click on image to enlarge)
http://www.chemistry.wustl.edu/~courses/genchem/LabTutorials/Thermochem/images/PhaseChanges.jpg