A collection of scientific resources about the motion of fluids like liquids and gases.

Nanotechnology: a general term covering nanoscale science and engineering. A more narrow definition is miniaturization engineering at the nanometer scale. Nano is a metric prefix meaning 'billionth', in this case, science, technology, and engineering at sizes measured in billionths of a meter, which is 1,000 times smaller than a micrometer. It is proposed to build electronic and mechanical devices which are made of very tiny parts (as are biotic systems), but which may have very large effects (as do biotic systems).

This category contains sites which assist with repairing, remodelling, and redecorating of the home. This includes not only its walls and rooms, but the contents within, like appliances and furniture. Sites are geared towards those with a do-it-yourself attitude, as well as those who would like to learn more before hiring someone to do it for them. This category does not include sites which sell goods and services online (Shopping: Home and Garden), sites for businesses that design or manufacture products (Business: Construction and Maintenance), or sites offering advice for purchasing decisions (Home: Consumer Information).

Sites in this category contain jokes, essays, songs, students' test answers and other humorous content pertaining to science, math, engineering and statistics.

The Solar System currently consists of the Sun, nine planets, and the many asteroids and comets that also orbit the Sun.

Electrochemistry is the study of the exchange of electrons between an ion/molecule and an electrode, or another ion/molecule. Application areas include batteries, plating or electrodeposition, corrosion, analytical electrochemistry, as well as the study of any chemical reaction involving oxidation or reduction.

This category is for sites specifically related to the technology of semiconductor electronics as a science. Submissions of sites dealing with manufacturing and production should be made to the appropriate subcategory elsewhere in the directory.

Technically oriented websites about the environmental aspects of agriculture, including agricultural pollution and its control.

Topics include climate change (or global warming), atmospheric C02, stratospheric ozone, desertification, and change indicators.

About the occurrence, hydrology, chemistry, water-supply development, water quality protection, and other aspects of groundwater (subsurface water).

Geomorphology deals with the study of landforms, their evolution, and the processes that shape the land's surface.

Geophysics involves the application of physical theories and measurements to discover the properties of the earth. The discipline dates to antiquity, mainly as a scientific approach to earthquake prediction (a problem still unsolved), but major progress began in the late 1500s with initial work in such areas as magnetism and gravity. Tremendous improvements in instrumentation in the early years of the 20th century generated rapid progress in geophysics and ultimately led, in the 1960s, to the theory of plate tectonics. Plate tectonics, the study of the interior structure of the earth, and such related areas as global and regional processes are known collectively as solid earth geophysics. The subdiscipline known as exploration geophysics involves the use of geophysical theory and instrumentation to locate petroleum and other mineral sources. Unlike solid earth geophysics, exploration geophysics generally concentrates on finding lateral heterogeneities in a relatively small part of the earth's crust. Geophysics is considered by some to be a branch of geology, by others to be of equal rank. It is distinguished from the other earth sciences largely by its use of instruments to make direct or indirect measurements of the parts of the Earth being studied, in contrast to the more direct observations which are typical of geology. The following definitions are from Robert E. Sheriff's Encyclopedic Dictionary of Applied Geophysics. 1. The study of the earth by quantitative physical method, especially by seismic reflection and refraction, gravity, magnetic, electrical, electromagnetic, and radioactivity methods. 2. The application of physical principles to studies of the earth. Includes the branches of (a) seismology (earthquakes and elastic waves); (b) geothermometry (heating of the earth, heat flow, volcanology, and hot springs); (c) hydrology (ground and surface water, sometimes including glaciology); (d) physical oceanography; (e) meteorology; (f) gravity and geodesy (the earth's gravitational field and the size and form of the earth); (g) atmospheric electricity and terrestrial magnetism (including ionosphere, Van Allen belts, telluric currents, etc.); (h) tectonophysics (geological processes in the earth); and (i) exploration and engineering geophysics. Geochronology (the dating of earth history) and geocosmogony (the origin of the earth) are sometimes added to the foregoing list. 3. Often refers to solid-earth geophysics only, thus excluding (c), (d), (e), and portions of other subjects from the above list. 4. Exploration geophysics is the use of seismic, gravity, magnetic, electrical, electromagnetic, etc., methods in the search for oil, gas, minerals, water, etc., with the objective of economic exploitation.

This category is for information about gemstones and their properties. Gemstones are generally regarded as: Polished fragments of 'precious' and 'semi-precious' minerals, used for decorative purposes. Examples of Precious Stones: Diamonds / Sapphires / Rubies / Emeralds Examples of Semi-Precious Stones: Topaz / Garnet / Spinels. Examples of Other stones used as gems: Jade / Agate / Opal

The geology of gold garners a level of interest that is out of proportion to its inherent scientific interest or its relative importance in technology and industry.

Includes sites on the specific properties of an environment where all of the matter has been evacuated (i.e. there would be nothing), as well as techniques and equipment for the attainment of such conditions in scientific investigations.

Classical mechanics generalized (extended) to realm of high velocities (special relativity), and strong gravitational fields (general relativity). In particular, the theory that time and space form a single 'spacetime' which is curved in the presence of energy and mass.

Sites belonging to NASA or sponsored by NASA. If a site is not directly NASA initiated or sponsored by NASA it belongs in another category.

This category is for plant, animal, and bacterial viruses. Viruses are non living small protein molecules. In the environment they are harmless, however, when they become into contact with a host cell from a plant or animal a sequence of degenerative events occurs. The virus inserts its own genomic material into the host cell and initiates DNA or RNA replication. The host cell burst spreading virions to infect other cells. The most common virus people are affected by is called Influenza. The category will cover a range of virus diseases, replication, database of structures, current research, images, and organizations.

Birds are warm-blooded, feather-bearing, egg-laying, amniotic vertebrates having the fore-limbs modified into wings. Ornithology is the scientific study of birds.