An example of figurative language in popular science writing:
"Already, more than a century ago, Faraday showed that a magnetic field can be thought of as a collection of lines of force that behave in many ways like elastic strings. So a magnetic field extending outwards from the Sun to the planetary material would behave like a vast aggregate of elastic strings. And as the Sun rotated the strings would become stretched and twisted into a structure rather like a clock-spring. By calculation it can be shown that rather a moderate magnetic field would be sufficient to give a clock-spring winding strong enough to maintain the required connexion from Sun to planets. In short, the torque that conveyed rotational momentum from the Sun to the planetary material was maintained by a magnetic clock-spring. …
Next we bring our clock-spring into action. The magnetic fields existing already inside the solar condensation provided a bridge between the primeval Sun and its newly grown disc. The magnetic field would become wound into a 'clock-spring' and rotational momentum began to pass from the Sun to the disc.
…once they had condensed from the gas these these materials were no longer subject to the clock-spring action of the magnetic field. …
Which stars are without planets? Almost certainly the rapidly spinning blue giants, and for a reason that is readily understood. Any attempt [sic] to transfer rotational momentum from these stars to an outlying planetary disc is frustrated, not by any lack of a magnetic clock-spring, but because the clock-spring becomes much too strong, It becomes so strong that the outlying disc gets blown completely away into space."
Fred Hoyle (1960) The Nature of the Universe (Revised ed.)
That a magnetic field behaved like elastic strings is a simile, although this then get used as a metaphor ("…as the Sun rotated the strings…") that is withour any marking to show the strongs were figurative. Similarly the structure the 'strings' formed was like a clock-spring (another simile); but again this is then used as a metaphor ("…we bring our clock-spring into action…").
Read about examples of science similes
