"Lecture Demonstration" is a

science fiction Science fiction (often shortened to sci-fi or abbreviated SF) is a genre of speculative fiction that deals with imaginative and futuristic concepts. These concepts may include information technology and robotics, biological manipulations, space ...

short story A short story is a piece of prose fiction. It can typically be read in a single sitting and focuses on a self-contained incident or series of linked incidents, with the intent of evoking a single effect or mood. The short story is one of the old ...

by American writer

Hal Clement Harry Clement Stubbs (May 30, 1922 – October 29, 2003), better known by the pen name Hal Clement, was an American people, American science fiction writer and a leader of the hard science fiction subgenre. He also painted astronomically oriented ...

. It was first published in '' Astounding: The John W Campbell Memorial Anthology'' in 1973. The story is set on the planet Mesklin as used in the author's novel ''

Mission of Gravity Mission (from Latin 'the act of sending out'), Missions or The Mission may refer to: Geography Australia *Mission River (Queensland) Canada *Mission, British Columbia, a district municipality *Mission, Calgary, Alberta, a neighbourhood *Ok ...

'', but in an earlier period when the college established by the Terrestrials is still being set up and the teachers as well as the students are still learning.

Plot summary

Dr LaVerne, a teacher with the college, takes a party of Mesklinite students on a geological expedition. Whilst examining a layer of rock, it collapses. LaVerne and the students fall into a cavern. They are unable to climb out; the limiting factor is time, as the teacher is enclosed in a suit with a finite

oxygen Oxygen is a chemical element; it has chemical symbol, symbol O and atomic number 8. It is a member of the chalcogen group (periodic table), group in the periodic table, a highly reactivity (chemistry), reactive nonmetal (chemistry), non ...

supply. The students and teacher discuss various possibilities until they realise that they can raise the melting point of the surrounding

ammonia Ammonia is an inorganic chemical compound of nitrogen and hydrogen with the chemical formula, formula . A Binary compounds of hydrogen, stable binary hydride and the simplest pnictogen hydride, ammonia is a colourless gas with a distinctive pu ...

'snow' to the point where it solidifies. They climb out to safety. 1973 short stories Science fiction short stories {{1970s-sf-story-stub