Name and Symbols of Different Physical Terms, Descriptions and SI Units

Base quantity	Symbol	Description	SI unit
Length	l	The one dimensional extent of an object.	metre (m)
Matter	m	The amount of matter in an object.

Important Physics Discoveries in Chronology Order

• 1687 - Laws of motion and law of gravity: Newton
• 1782 - Conservation of matter: Lavoisier 
• 1785 - Inverse square law for electric charges confirmed: Coulomb 
• 1801 - Wave theory of light: Young

Inventions, Inventor, Country and Year

• Adrenaline: (isolation of) John Jacob Abel, U.S., 1897.
• Aerosol can: Erik Rotheim, Norway, 1926.
• Air brake: George Westinghouse, U.S., 1868.
• Air conditioning: Willis Carrier, U.S., 1911.

List of Scientific Instruments and Uses

• Absorptiometer - Instrument for measuring solubility of gases in liquids
• Accelerometer - Instrument for measuring acceleration or vibrations
• Acetimeter - Instrument for measuring strength of vinegar
• Acidimeter - Instrument for measuring concentration of acids
• Actinograph - Instrument used to calculate time of photographic exposure

Units

Unit: A unit of measurement is a definite magnitude of a physical quantity, defined and adopted by convention and/or by law, that is used as a standard for measurement of the same physical quantity. Any other value of the physical quantity can be expressed as a simple multiple of the unit of measurement.

Chemistry Fun and Facts

• The only elements that are liquid at room temperature are bromine and mercury.
• Water expands as it freezes. An ice cube takes up about 9% more volume than the water used to make it.
• If you pour a handful of salt into a full glass of water, the water level will actually go down rather than overflowing the glass.