Study Point

  A   spacecraft   is a vehicle or machine designed to   fly in outer space . A type of   artificial satellite , spacecraft are used for a variety of purposes, including   communications ,   Earth observation ,   meteorology ,   navigation ,   space colonization ,   planetary exploration , and   transportation   of   humans   and   cargo . All spacecraft except   single-stage-to-orbit   vehicles cannot get into space on their own, and require a   launch vehicle   (carrier rocket). On a  sub-orbital spaceflight , a  space vehicle  enters  space  and then returns to the surface, without having gained sufficient energy or velocity to make a full  orbit  of the Earth. For  orbital spaceflights , spacecraft enter closed orbits around the  Earth  or around other  celestial bodies . Spacecraft used for human spaceflight carry people on board...

  In   physics , a   state of matter   is one of the distinct forms in which   matter   can exist. Four states of matter are observable in everyday life:   solid ,   liquid ,   gas , and   plasma . Many intermediate states are known to exist, such as   liquid crystal , and some states only exist under extreme conditions, such as   Bose–Einstein condensates ,   neutron-degenerate matter , and   quark–gluon plasma , which only occur, respectively, in situations of extreme cold, extreme density, and extremely high energy. For a complete list of all exotic states of matter, see the   list of states of matter . Historically, the distinction is made based on qualitative differences in properties. Matter in the solid state maintains a fixed volume and shape, with component particles ( atoms ,  molecules  or  ions ) close together and fixed into place. Matter in the liquid state maintains a fixed volume, b...

  In   condensed matter physics , a   Bose–Einstein condensate   ( BEC ) is a   state of matter   (also called the fifth state of matter) which is typically formed when a   gas   of   bosons   at low   densities   is cooled to   temperatures   very close to   absolute zero   (−273.15 °C or −459.67 °F). Under such conditions, a large fraction of bosons occupy the lowest   quantum state , at which point microscopic   quantum mechanical   phenomena, particularly   wavefunction interference , become apparent   macroscopically . A BEC is formed by cooling a gas of extremely low density (about one-hundred-thousandth (1/100,000) the density of   normal air ) to ultra-low temperatures. This state was first predicted, generally, in 1924–1925 by  Albert Einstein  following and crediting a pioneering paper by  Satyendra Nath Bose  on the new field now known as...

 Anything that occupies space and have mass is called matter In  classical physics  and general  chemistry ,  matter  is any substance that has  mass  and takes up space by having  volume . All everyday objects that can be touched are ultimately composed of  atoms , which are made up of interacting  subatomic particles , and in everyday as well as scientific usage, "matter" generally includes  atoms  and anything made up of them, and any particles (or  combination of particles ) that act as if they have both  rest mass  and volume. However it does not include  massless particles  such as  photons , or other energy phenomena or waves such as  light . Matter exists in various  states  (also known as  phases ). These include classical everyday phases such as  solid ,  liquid , and  gas  – for example  water  exists as ice, liquid water, ...

  Electricity   is the set of   physical   phenomena   associated with the presence and   motion   of   matter   that has a property of   electric charge . Electricity is related to   magnetism , both being part of the phenomenon of   electromagnetism , as described by   Maxwell's equations . Various common phenomena are related to electricity, including   lightning ,   static electricity ,   electric heating ,   electric discharges   and many others. The presence of an  electric charge , which can be either positive or negative, produces an  electric field . The movement of  electric charges  is an  electric current  and produces a  magnetic field . When a charge is placed in a location with a non-zero electric field, a force will act on it. The magnitude of this force is given by  Coulomb's law . If the charge moves, the electric field would be doing  ...