The National Science Resources Center says that density is one of the characteristic properties of an object, which, when compared to the densities of other known objects, allows an investigator to identify the materials from which it is made. While several materials may have similar densities, this property allows an individual to rule out unlikely candidates and use further tests to confirm identification.Know More
Reference.com defines density as the ratio of an object's volume to its mass. Several factors affect density and it sometimes varies slightly from one sample to the next. Density varies with temperature as many materials expand upon heating. In addition, the density of a gas increases as pressure increases. When speaking of the density of a gas, scientists often specify the standard temperature and pressure to eliminate these variables. Managing these conditions is essential if one is using density to identify a gas.
Specific gravity relates to density. It is the ratio of the material as compared to water and carries no units. About.com says objects with specific gravities greater than 1 sink in water, while those with a specific gravity of less than 1 float. This quick test of nonsoluble items helps to eliminate possible choices when identifying a solid.Learn more about Thermodynamics
Two objects in physical contact with each other are in thermal equilibrium when they reach the same temperature and an exchange of heat energy no longer occurs. According to HyperPhysics, the relation of thermal equilibrium follows the Zeroth Law of Thermodynamics, which states that “if two systems are at the same time in thermal equilibrium with a third system, they are in thermal equilibrium with each other.”Full Answer >
When any item burns, the reaction involves the consumed material and oxygen, so without oxygen, candles (and any other objects) do not burn. In a closed system without air flow, a candle's flame consumes all of the available oxygen before extinguishing.Full Answer >
The momentum of a system is conserved in elastic collisions between system objects. The system must be isolated, indicating that it is free from the influence of a net, external altering force that affects collision processes, such as gravity.Full Answer >
Thermal energy is made by the movement of particles within an object or system. The thermal energy of an object, and thus the temperature of an object, increases as its molecules move more quickly.Full Answer >