A topic in Learners' conceptions and thinking
There are many ideas that have been mooted in the history of science (and, before science was formally recognised, 'natural philosophy') that are no longer used in scientific discourse today (phlogiston, caloric, the luminiferous ether….)
Some of the alternative conceptions listed below might be seen as lay ideas (folk notions) but many were seriously considered by scientists / natural philosophers.
Read about historical scientific conceptions
Some historical examples of notions about the natural world (that would now be considered alternative conceptions)
anatomy and physiology
atoms
caloric
cold
(Cold being considered as an entity in its own right, distinct from heat)
- atoms of cold are tetrahedral
- cold will force its way through gaps
- ice continues to be a source of cold till melted
- matter can be attacked by cold
- we are but limited in the art of increasing the cold of bodies
cosmology
- heavenly bodies naturally revolve because they are spherical
- heavenly bodies only move with circular motion
- planets move around the earth embedded in concentric spheres
- the heavens are not liable to change and decay
- Venus sits on a sphere which rotates independently as it moves with a sphere that rotates around the earth
elements
- elements aspire to reach their proper spheres
- expanded air would become fire
- flame will be happy and contented when it reaches its own region of the world
- substances get heavier when burned because fire particles attach to the burned matter
- worldly matter is composed of four elements
ether (æther or luminiferous ether)
- atoms are vortexes in the ether
- comets stir up the aether
- ether prevents the Moon falling into the Earth
- gravity is a tendency to move to where the ether is rarer
- heavenly bodies and celestial spheres are made from a special ethereal substance
- heavenly spheres are formed of a very subtle ethereal substance
- light travels as impulses between particles in the ether
- phlogiston weakened the repulsion between substance particles and ether
- planets are formed of a fifth element
- planets are made from ether
- very subtle aether pervades and fills all things
read about the luminiferous aether
levity
- comet tails contain levitating material
- fire and air have levity and tend to rise
- levity as a natural force
- phlogiston might have negative weight
magnetism
metals
motion
- falling body accelerates as it gets near home (followers of Aristotle)
- heavenly bodies only move with circular motion
- impetus of a projectile gradually fades away like the reverberations in a bell long after it has been struck (Galileo)
- projectile will abruptly fall to earth in a sheer vertical drop (Aristotle)
phlogiston
- fire is a chemical element released in combustion
- hydrogen is water deprived of its phlogiston,
- inflammable air might be phlogiston
- oxygen is phlogisticated water
- phlogiston might have negative weight
- phlogiston refuses aqueous solution
- phlogiston weakened the repulsion between substance particles and ether
- simple sulphureous substances contain phlogiston
phrenology
- from what I see of your head you are the man (George Stephenson)
preformationism
solar system
- comets are formed out of exhalations from the earth
- crystal spheres had enjoyed the happiness of circular motion
- the planets were formed after a comet knocked material out from the sun
- solar heat derives from burning coal
