# Science and Technology

### Science is neither a completed book nor a set of temporary beliefs

We should think of science as a complex web of ideas, facts, philosophical concepts, history, and serendipity.

What makes science special is that knowledge, once acquired, can be put to use to change the way human beings live.

ohm
An SI unite (symbol Ω, Greek omega) of electrical resistance (the property of a conductor when a potential difference of 1 volt produces a current of 1 ampere and which restricts the flow of electrons through it).

The symbol Ω, the Greek capital letter of omega, unfortunately is not supported by some computer browsers.

Ohm's Law
A rule devised by Georg Simon Ohm, a 19th-century German physicist, to formulate the relationship between the electric current passing through the material of an electrical circuit and the resistance of the material in the electrical circuit.

The basic statement made by Ohm's law is that the current in any circuit is proportional to the voltage that is applied to the circuit.

The value of the resistance depends on the material of which the circuit is made and varies with the temperature of the material. A pure metal whose temperature is drastically reduced usually has its resistivity lowered by many orders of magnitude.

Ohm's law is extremely useful in the design and analysis of electric circuits made of many different kinds of material.

Ohm, Georg Simon (1789-1854)
A German physicist who studied electricity and discovered the fundamental law that bears his name.

The SI unit of electrical resistance, the ohm, is named for him, and the unit of conductance (the inverse of resistance) was formerly called the mho, which is "ohm" spelled backward.

protein crystallography
A method of determining the arrangement of atoms within a crystal, in which a beam of X-rays strikes a crystal and scatters into many different directions.

From the angles and intensities of these scattered beams, a crystallographer can produce a three-dimensional picture of the density of electrons within the crystal.

science
1. The study of the physical and natural world and phenomena, especially by using systematic observation and experiment.
2. An activity that is the object of careful study or which is carried out according to a developed method.
3. To confuse or to overwhelm someone by giving an impenetrable explanation using technical terms and concepts.
• Modern medicine depends intimately on information about the details of the molecular machinery of living systems obtained over the past five decades, or more.
• The far-flung information systems depend on scientific information about electromagnetic waves obtained over a century ago and on the understanding of new kinds of materials that may be only a few years old.
• Scientists now specialize, both by field and by the kind of work they do; some scientists study stars, others study cells, yet others atoms or quarks.
• The balance between what is experimentally known because it has been seen; that is, measured, detected, or tested; and what is theoretically known because it is thought by some scientists that that's how it might be; that it is, which it must be, or it ought to be are all intrinsic to the advances of science.
synchrotron
A ring-shaped subatomic particle accelerator that is used both for the study of subatomic particles and for the production of radiation.

Particle beams from synchrotron accelerators can be used in medical treatment, in medical and biological research, and in physics.

The name of the synchrotron is derived from the way in which particles are accelerated: a beam of particles is kept in step with an oscillating radio-frequency acceleration voltage as the particles circle the accelerator ring.

In a typical synchrotron, a particle will travel millions of miles in an evacuated pipe only a few inches in diameter.

The phase stability that makes the synchrotron possible was discovered in the 1940s by V.I. Veksler, a Soviet physicist, and E.M. McMillan, an American physicist who proposed the name of the machine.

McMillan designed an electron synchrotron with a beam energy of 300 MeV (million electric volts), built at the Lawrence Berkeley Laboratory in California.

You may see the bibliographic list of sources of information for these scientific presentations.

Index of additional Scientific and Technological Topics.