Matter And Energy

Matter is anything that occupies space and has mass. Energy is the ability of matter to do work.

• Chemical Nature of Matter
• Atoms - The smallest unit of matter which can exist. (there are currently 109 known elements)
• Protons - Are the positively charged elements of the atom.
• Neutrons - Are the neutrally charged elements of the atom.
• Electrons - Are the negatively charged elements of the atom.
• Nucleus - Protons and Neutrons make up the center of the atom and the electrons orbit around it.
• Molecules - The bonding of atoms create molecules. (Hydrogen is made of up of one electron and one proton)
• Physical Nature of Matter
• Solid -A solid has a definite volume and shame and is independent of its container.
• Liquid- When changing from a solid to a liquid the volume does not change but the material can now conform to it's container.
• Liquids are also incompressible
• Surface Tension - In a liquid the molecules still partially bond together
• Gas- Gasses differ from solids and liquids in that they have neither a definite shape nor volume.
• Weight and Mass
• Weight - Weight is the force which gravity attracts a mass.
• The force of gravity varies with the distance between a body and the center of the earth.
• Mass - Described as the amount of matter in an object and is constant regardless of its location.
• To find mass Mass = Weight / Acceleration due to gravity (32.2 feet per- second )
• Slug - is a unit of mass that is equivalent to the approximately 32.175 pounts under standard atmospheric conditions.
• Density - The density of a substance is its weight per unit volume.
• The density of solids and liquids vary with temperature however the density of gas varies with temperature and pressure.
• To find Density Density = Weight / Volume
• Specific Gravity - Is a comparison of one substance to that of another.
• Densities of solids and liquids are compared to water at 4 degrees Celsius and gasses are compared to air.
• Specific gravity is independent of the size of the sample under consideration and varies only with the substance the sample is made of.
• Hydrometer - Is a device used to measure the specific gravity of liquids.
• Energy
• Potential Energy - Energy stored in a material, even though the object is not doing work.
• Kinetic Energy - When Potential Energy is release and causes motion it is changed to kinetic energy.
• Units of Energy - Most common used to measure energy is the Horsepower and is equivalent to 33,000 foot pounds of work done in one minute. In the metric system is the Joule.

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page revision: 4, last edited: 02 Oct 2008 22:46