Science Development - Zone 2 - Expo Seattle 1962
The flow of traffic in Zone 2 is channelled so that the exhibits and displays are viewed in orderly sequences. There are five general sections, each representing a facet of the development of science.
The first is a gallery with a spectacular display of wall photographs and films on some of the aspects of nature that have aroused human curiosity. They range from the mood and violence of a volcanic eruption to the serenity of summer scenes.
Then comes a corridor where the unreliability and limitations of human senses are graphically highlighted. A series of exposures involving sight, hearing and touch provoke a set of misperceptions. Two balloons, alternately inflated and deflated, give the impression of forward and backward movement, seen from a distance. A false horizon distorts any vertical reference in a Western scene. The sound of a train makes it seem as if it is moving. The touch of concentric loops of hot and cold tubes gives a burning sensation. A film presentation shows the range of sounds beyond human hearing, ultraviolet and infrared demonstrations show visual limitations.
To measure particles that are too small for the eye or to capture spaces that are too large for the mind, science has had to develop precision instruments and special techniques. Some of these are presented in the next series of measurement exhibitions.
Typical counters and devices for measuring atomic phenomena are in operation in front of a model of a reactor wall. Optical, electron and ion microscopes are explained and their functions demonstrated. The different tools and techniques astronomers and astrophysicists use to measure the distance and size of stars and the intensity of their light are presented. And visitors can see their weight and size measured scientifically.
Arithmetic - mathematics - is taken up in the next series of exhibitions. The displays show the necessity of numbers, what they mean, how they work and how they are recorded and manipulated. They also graphically demonstrate the logic of mathematics, certain geometric relationships, and algebraic principles.
Man has built machines to speed up the process of calculating from the abacus through electronic "brains". Examples of these instruments and some of the mathematical tools are shown on a screen.
The triumphant history of man's quest for knowledge of his universe. At different times in different fields, spectacular discoveries of hidden truths pave the way for a general advancement of knowledge or a whole new set of scientific achievements.
In the last section of Zone 2, a series of animated exhibits recall some of the greatest breakthroughs. The experiments are listed here in order.
In electromagnetism:
Important discoveries by Galvani, Volta, Oersted and Faraday.
Summary of Faraday's panel "lines of force" field theory.
Faraday-and-one dynamo device, laptops.
Maxwell-mathematical description of electromagnetic field, light related to electricity and magnetism.
Hertz-experiment proving Maxwell's theory and demonstrating the behaviour of "Hertzian" waves.
- Table of electromagnetic spectra.
In atomic-molecular research:
1) The concept of three states of matter is illustrated using samples of H2O in the three states: water vapour, water and ice. The states of matter were known in the 18th century, but the fundamental unity of matter was not understood.
2) The foundation of atomicity of the principles of Lavoisier's theory of constant composition of compounds consisting of discrete elements is presented. Then there are Dalton's theories that each element consists of identical atoms that are indestructible and cannot be divided, created or destroyed, and that when two or more elements come together to form compounds their atoms unite to form molecules of the compound.
Avogadro: An abstract three-dimensional action model shows Avogadro's law: a constant number of molecules in equal volumes of gas.
Mendeleev: Mendeleev's Periodic Table of the Elements shows the arrangement of elements in atomic weight and the discovery that elements with similar properties recur at defined intervals.
A summary panel on these discoveries, by the year 1895 scientists thought they had a final understanding of the fundamental composition of matter in the form of tiny particles, called atoms, which are indivisible. The following year, a series of discoveries exploded the theory of the indivisibility of atoms and opened new frontiers for the study of the fundamental structure of matter.
JJ Thomson: a public-operated device demonstrating the energy and mass of the electron illustrates Thomson's discovery of the electron", which launched the idea that atoms can be made up of smaller particles.
Discovery of particle emission from some atoms: Roentgen discovered X-rays; Becquerel discovered radioactivity; Curie discovered polonium and radium.
8) Rutherford: a description of his "scattering" experiment in which he determined that the atom has an enormous amount of empty space with a heavy positively charged nucleus surrounded by a negative charge, the electrons.
9) Planck-Bohr: A three-dimensional representation is presented of a model of the atom postulated by Bohr and based on the application of Planck's quantum hypothesis to Rutherford's model of the atom.
The model shows the atom as a "solar system in miniature" with its electrons revolving around the nucleus in specific orbits. Bohr's model of the atom, consisting of electrons and protons, again seemed to be the ultimate explanation of the atomic structure. Then, a new discovery once again opened the way to a deeper study of the fundamental structure of matter.
Chadwick: a pictorial presentation of the cloud chamber experiment that led to the discovery of the neutron and its identification as a brand new electrically neutral particle.
Fundamental particles: a graph showing the fundamental particles known to date. The search for new particles is still ongoing.
The modern concept of molecular structure, a large three-dimensional model of a simple molecule illustrates the bonding of atoms in molecules.
In genetics:
1) Darwin: a re-creation of the voyage of HMS Beagle, using projected background photos of movement and animals seen by Darwin. Animals played a role in his formulation of the theory of natural selection as the mechanism that drove the evolutionary process. Darwin, not knowing the mechanism of heredity, could not explain how favourable traits are transmitted from generation to generation. Mendel's laws began to explain how natural selection could be perpetuated across species.
2) Re-creation of Mendela's famous pea plant experiment, in a stylised garden, using live flowers to demonstrate Mendel's laws.
Thomas Hunt Morgan: a pictorial and animated presentation demonstrates Morgan's explanation of the role of chromosomes and their relationship to genes, showing giant salivary gland chromosomes in Drosophila.
Muller: a comparison of normal and mutated Drosophila and their chromosomes to illustrate Muller's discovery that mutations in living organisms can be produced artificially by x-ray irradiation.
5) Beadle and Tatum: an explanation of how genes control hereditary processes through enzymes (one gene, one enzyme hypothesis) through a pictorial presentation of Beadle-Tatum's experiments with abnormal Neurospora that have lost their genes necessary to produce some of the enzymes involved in nutrition (and growth) processes.
Transformation: a cinematic presentation of the transformation experiment in which a resistant strain of dead pneumococci and a live resistant non-strain are mixed and injected into a mouse. Eventually, the tissues of the infected mouse are resistant to pneumococci.
Avery, MacLeod and McCarty: a graphic display of their identification of deoxyribonucleic acid (DNA) as the principle of transformation in experiment six.
Watson and Crick: a presentation of their image of a DNA molecule of a double helix and an explanation of the arrangement of the series of molecular helices, highlighted by a large three-dimensional model of a DNA molecule.
In space:
Tycho Brahe: a replica of the armillary sphere (or spherical astrolabe) to represent his precise measurement of planetary motions.
Development of the heliocentric idea of the solar system-three short animated films on three adjacent screens present: Ptolemy (geocentric concept, circular orbits of the planets and sun); Copernicus (sun is the centre, circular planetary orbits); Kepler (planetary laws based on Brahe's measurements, sun is the centre of planetary ellipses orbits).
Galileo, a presentation of the theory of falling bodies; an adaptation of his experiment on an inclined plane.
Newton: The universal law of gravitation is shown in a three dimensional presentation showing that Newton combined Kepler's laws of planetary motion and Galileo's study of falling bodies into the law of universal gravitation.
5) Einstein: a demonstration of the extension of Newton's law of universal gravitation into the theory of general relativity.
Einstein: the theory that motion is relative to a certain arbitrarily chosen frame of reference is demonstrated by a simulation of twin rockets travelling at different speeds.
An animated model of the earth, showing the movement of the earth in 4 dimensions.
Article based on Official Books Seattle World's Fair 1962