K

kaleidoscope - a type of optical toy that gives multiple images from two inclined mirrors
Keck telescope - a 10m diameter reflecting telescope at Mauna Kea Observatory in Hawaii
kellner - type of telescope eyepiece with a wide and flat firled
Kelvin - (K) the unit of thermodynamic temperature (1/273.16 of triple point of water)
Kepler's laws - three laws of planetary motion (1609 -1619)
kerr cell - electro-optic shutter, rotates plane of polarisation when electric field is on
kilogram (kg) - unit of mass
kiloparsec - one thousand parsecs
kilowatt (kW) - unit of power (= 1000 W)
kilowatt hour - unit of energy, one kilowatt used for one hour
kinematics - study of the motion of objects without reference to why they move
kinetic - movement or motion, as in kinetic energy
kinetic energy - energy of a body due to its motion
kinetic theory - explanations of phenomena (such as gas laws) by molecular motion
Kirchoff's laws - laws for electrical circuit networks
Kundt's tube - a resonance tube containing dust used to measure the speed of sound