Balance wheelA balance wheel, or balance, is the timekeeping device used in mechanical watches and small clocks, analogous to the pendulum in a pendulum clock. It is a weighted wheel that rotates back and forth, being returned toward its center position by a spiral torsion spring, known as the balance spring or hairspring. It is driven by the escapement, which transforms the rotating motion of the watch gear train into impulses delivered to the balance wheel.
Mechanical equilibriumIn classical mechanics, a particle is in mechanical equilibrium if the net force on that particle is zero. By extension, a physical system made up of many parts is in mechanical equilibrium if the net force on each of its individual parts is zero. In addition to defining mechanical equilibrium in terms of force, there are many alternative definitions for mechanical equilibrium which are all mathematically equivalent. In terms of momentum, a system is in equilibrium if the momentum of its parts is all constant.
Metric signatureIn mathematics, the signature (v, p, r) of a metric tensor g (or equivalently, a real quadratic form thought of as a real symmetric bilinear form on a finite-dimensional vector space) is the number (counted with multiplicity) of positive, negative and zero eigenvalues of the real symmetric matrix gab of the metric tensor with respect to a basis. In relativistic physics, the v represents the time or virtual dimension, and the p for the space and physical dimension.
Electric dipole momentThe electric dipole moment is a measure of the separation of positive and negative electrical charges within a system, that is, a measure of the system's overall polarity. The SI unit for electric dipole moment is the coulomb-meter (C⋅m). The debye (D) is another unit of measurement used in atomic physics and chemistry. Theoretically, an electric dipole is defined by the first-order term of the multipole expansion; it consists of two equal and opposite charges that are infinitesimally close together, although real dipoles have separated charge.
History of science and technology in MexicoThe history of science and technology in Mexico spans many years. Indigenous Mesoamerican civilizations developed mathematics, astronomy, and calendrics, and solved technological problems of water management for agriculture and flood control in Central Mexico. Following the Spanish conquest in 1521, New Spain (colonial Mexico) was brought into the European sphere of science and technology. The Royal and Pontifical University of Mexico, established in 1551, was a hub of intellectual and religious development in colonial Mexico for over a century.
Natural scientific research in CanadaThis article outlines the history of natural scientific research in Canada, including physics, astronomy, space science, geology, oceanography, chemistry, biology, and medical research. Neither the social sciences nor the formal sciences are treated here. The early European explorers were responsible for charting much of what would become the east and west coasts of Canada as well as the Arctic. John Cabot, the Italian explorer sailing under the English flag made two voyages to North America in 1497 and 1498 along the coast of what is now called Newfoundland.
Instant messagingInstant messaging (IM) technology is a type of online chat allowing real-time text transmission over the Internet or another computer network. Messages are typically transmitted between two or more parties, when each user inputs text and triggers a transmission to the recipient(s), who are all connected on a common network. It differs from email in that conversations over instant messaging happen in real-time (hence "instant").
