Final answer:
Cooling a substance generally causes the particles to slow down and come closer together, resulting in a smaller volume and increased density. This behavior is central to understand substance properties in chemistry, especially as it relates to temperature changes and the physical state of matter.
Step-by-step explanation:
The behavior of substances in response to temperature changes is a fundamental concept in chemistry. When a substance is cooled, the kinetic energy of its particles decreases, leading to a reduction in particle movement. As a result, the particles move slightly closer together, occupying a smaller volume and thus increasing the density of the substance. Atoms and molecules are packed tightly in solids and liquids, while they are separated by empty space in gases, resulting in lower densities in gaseous states. The state of a substance is also influenced by intermolecular forces and kinetic energy, both of which are affected by temperature and pressure changes.
As for exceptions, ice exhibits a unique characteristic where it is less dense than liquid water due to the structured lattice that forms upon freezing, introducing spaces that are not found in the liquid state. It is also noteworthy that most materials, aside from water, contract when cooled and expand when heated, leading to fluctuations in density according to thermal expansion or contraction.
In summary, the physical state of a substance can be altered through heating or cooling, which changes the kinetic energy and spacing between particles. This can result in state changes such as the transition from gas to liquid or liquid to solid at lower temperatures, with a dramatic decrease in volume when gases condense to liquids.