THE VOCABULARY
Instruments, concepts, and phenomena — the shared vocabulary of the site.
astrolabe
Ancient inclinometer and analog computer for astronomical calculations, used for position, time, and star identification.
Faraday cage
A conducting enclosure that blocks external static and low-frequency electric fields by redistributing charge on its surface.
gyroscope
A rapidly spinning rotor on a gimbal or pivot, whose angular momentum resists reorientation — the workhorse of modern inertial navigation.
lever
A rigid bar pivoting about a fulcrum, trading applied force against distance to achieve mechanical advantage.
Optical fiber
A thin glass fibre of core + cladding structure that guides light by total internal reflection along its length. Loss < 0.2 dB/km at 1.55 μm in silica single-mode fibre; the backbone of global telecommunications.
pendulum clock
Mechanical clock regulated by a swinging pendulum; first accurate timekeeper, built by Huygens in 1656.
quadrant
Pre-telescope astronomical instrument for measuring the angular position of stars and planets.
Resistor
A two-terminal passive electrical component designed to present a specific resistance to current flow. Values range from milliohms to gigaohms; tolerances from 10% to 0.01%.
Solenoid
A long, tightly wound helical coil of wire. Carrying a current, it produces a uniform magnetic field along its axis: B = μ₀ n I.
telescope
Optical instrument that gathers light and magnifies distant objects; from Newton's 1668 reflector to the James Webb Space Telescope.
Toroid
A coil wound into a doughnut shape. Confines its magnetic field almost entirely to the interior of the doughnut: B = μ₀ N I / (2πr).
Transformer
A two-coil magnetic device that converts AC voltage up or down by the turn ratio: V₂/V₁ = N₂/N₁. The enabler of the electrical power grid.