SCI10: WHAT IS THE PHYSICAL WORLD?
(The Grand Design)
Physical world
- includes the inanimate objects in the
universe, which range in scale from
the submicroscopic to the
cosmological
- these include elementary particles,
light and heavy elements, stars,
galaxies, and planetary systems;
molecules and supramolecules and
aggregates; and the earth and its
spheres – the geosphere,
atmosphere, and hydrosphere.
2 Natures of Reality
1. classical science
- the physical world was
considered real (it exists) to
the extent that is could be
perceived through the
senses
- this is based on the
philosophical concept realism
- all things that are visible to
the naked eye is part of the
physical world
Realism
- The existence of the physical
world is based from what is
seen by the observer
- perceived
2. Modern science
- redefined this by introducing
a concept called
model-dependent realism
- Uses model-dependent
realism to define the physical
world
- uses models or
representations to define
things that are part of the
physical world
Model-dependent Realism
- It is pointless to ask whether
a model is real, only whether
it agrees with an observation
- Corresponds to the way we
perceive things
- Solves or at least avoids the
meaning of existence
- this concept makes use of
models or representations of
objects to define their
physical properties.
Elements of a Good Model
1. Elegant
- An element of a good model
which avoids unnecessary
complexity and focuses on
the most fundamental
principles
2. Contains a few arbitrary or
adjustable elements.
-
3. Agrees with and explains all existing
observations
4. Makes detailed predictions about
future observations that can
disprove or falsify the model if they
are not borne out
J.J. Thompson Plum Pudding Model
- Negatively-charged electrons
embedded within a
positively-charged “soup”
