Wikipedia:Contents/Outlines/Natural and physical sciences

Science – systematic enterprise that builds and organizes knowledge in the form of testable explanations and predictions about the world. An older and closely related meaning still in use today is that of Aristotle, for whom scientific knowledge was a body of reliable knowledge that can be logically and rationally explained.

Basis of natural science – natural science is a major branch of science, that tries to explain and predict nature's phenomena, based on empirical evidence. In natural science, hypotheses must be verified scientifically to be regarded as scientific theory. Validity, accuracy, and social mechanisms ensuring quality control, such as peer review and repeatability of findings, are amongst the criteria and methods used for this purpose.

Scientific method – body of techniques for investigating phenomena, acquiring new knowledge, or correcting and integrating previous knowledge. To be termed scientific, a method of inquiry must be based on gathering empirical and measurable evidence subject to specific principles of reasoning.
Metric system – decimal based system of measurement based on the metre and the kilogram, units of measure that were developed in France in 1799 and which is now used in most branches on international commerce, science and engineering.

Branches of natural science – also called "the natural sciences", which are:

Biology – study of life and living organisms, including their structure, function, growth, origin, evolution, distribution, and taxonomy.
- Biological phenomena
  - Death – cessation of life; end of life-cycle
- Branches of biology
  - Anatomy – study of the structure of living things.
    - Human nervous system – part of the human body that coordinates a person's voluntary and involuntary actions and transmits signals between different parts of the body.
      - Human brain – central organ of the nervous system located in the head of a human being, protected by the skull
  - Biochemistry – interdisciplinary field at the nexus of biology and chemistry, elucidating the molecular processes that underpin life. Investigating the structure, function, and interactions of biological molecules, biochemists explore the intricate mechanisms within cells and organisms. Central themes include enzymes catalyzing biochemical reactions, DNA's genetic information storage, and the synthesis of proteins. Understanding cellular metabolism, signal transduction, and molecular genetics, biochemistry plays a pivotal role in advancing medical research, biotechnology, and pharmacology. Analyzing the molecular intricacies of life, biochemistry not only unlocks the secrets of biological phenomena but also informs innovations in medicine and the development of novel therapies.
  - Biophysics – interdisciplinary science that uses the methods of physical science to study biological systems. Studies included under the branches of biophysics span all levels of biological organization, from the molecular scale to whole organisms and ecosystems.
  - Botany – a branch of biology, focuses on the study of plants, encompassing their structure, physiology, classification, and ecology. Botanists explore plant life at various levels, from cellular processes to entire ecosystems. This scientific discipline contributes crucial insights into plant evolution, growth patterns, and interactions with the environment. Understanding botany is essential for agricultural advancements, environmental conservation, and the development of sustainable practices. From microscopic algae to towering trees, botany unravels the mysteries of plant life, fostering appreciation for the diverse and vital role plants play in the world.
  - Cell biology – study of cells. Their physiological properties, their structure, the organelles they contain, interactions with their environment, their life cycle, division and death.
  - Ecology – study of interactions between organisms and their environment.
  - Environmental studies – multidisciplinary academic field that systematically studies human interaction with the environment, bringing together principles of the physical sciences, commerce/economics and social sciences to solve today's complex contemporary environmental problems.
    - Air pollution dispersion – distribution of air pollution, the study of which is used by many regulatory agencies to control air pollution
  - Evolution – study of evolutionary processes that produced the diversity of life on Earth.
  - Genetics – study of genes, heredity, and variation in living organisms.
  - Immunology – study of immune systems in all organisms.
  - Neuroscience – scientific study of the nervous system.
    - Brain mapping – neuroscience techniques for making spatial maps of the (human or non-human) brain.
  - Paleontology – study of prehistoric life, including organisms' evolution and interactions with each other and their environments (their paleoecology).
    - Dinosaurs – diverse group of animals that were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period (about 230 million years ago) until the end of the Cretaceous (about 65 million years ago), when the Cretaceous–Paleogene extinction event led to the extinction of most dinosaur species at the close of the Mesozoic era.
  - Pharmacology – broadly defined as the study of drug action and pharmacokinetics.
  - Physiology – study of how living organisms function.
  - Zoology – study of the animal kingdom, including the structure, embryology, evolution, classification, habits, and distribution of all animals, both living and extinct.
- Life forms – living organisms
  - Animals – multicellular, eukaryotic organisms of the kingdom Animalia (also called Metazoa). All animals are motile, meaning they can move spontaneously and independently at some point in their lives. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their lives. All animals are heterotrophs: they must ingest other organisms or their products for sustenance.
    - Ants – more than 12,000 species of social insects evolved from wasp-like ancestors, that live in organised colonies which may consist of millions of ants.
    - Gastropods – any member of the class Gastropoda, which includes slugs and snails.
    - Reptiles – group of tetrapods with an ectothermic ('cold-blooded') metabolism and amniotic development. Includes turtles, crocodilians, lizards and snakes, and tuatara.
    - Birds – feathered, winged, bipedal, endothermic (warm-blooded), egg-laying, vertebrate animals. There are about 10,000 living species of birds.
    - Fish – any member of a paraphyletic group of organisms that consist of all gill-bearing aquatic craniate animals that lack limbs with digits.
      - Sharks – type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago.
  - Fungi – group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms.
    - Lichens – composite organisms made up of one or more fungal partners and one or more photosynthetic partners (either algae or cyanobacteria)
  - Extraterrestrial life – life that may occur outside Earth and which did not originate on Earth.
Physical sciences – encompasses the branches of science that study non-living systems, in contrast to the life sciences. However, the term "physical" creates an unintended, somewhat arbitrary distinction, since many branches of physical science also study biological phenomena.
- Chemistry – study of matter, especially its properties, structure, composition, behavior, reactions, interactions and the changes it undergoes.
  - Organic chemistry – study of the structure, properties, composition, reactions, and preparation (by synthesis or by other means) of carbon-based compounds, hydrocarbons, and their derivatives.
  - Water – chemical substance with the chemical formula H₂O. Its molecule contains one oxygen and two hydrogen atoms connected by covalent bonds. Water is a liquid at ambient conditions, but it often co-exists on Earth with its solid state, ice, and gaseous state (water vapor or steam).
  - Alchemy – protoscience considered a predecessor to chemistry
- Earth science – all-embracing term for the sciences related to the planet Earth. It is arguably a special case in planetary science, the Earth being the only known life-bearing planet.
  - Earth – planet you are on right now. Third planet from the Sun, the densest planet in the Solar System, the largest of the Solar System's four terrestrial planets, and the only astronomical object known to harbor life.
  - Geography – study of the Earth and its lands, features, inhabitants, and phenomena. A literal translation would be "to describe or write about the Earth".
  - Geology – study of the Earth, with the general exclusion of present-day life, flow within the ocean, and the atmosphere. The field of geology encompasses the composition, structure, physical properties, and history of Earth's components, and the processes by which they are shaped. Geologists typically study rock, sediment, soil, rivers, and natural resources.
  - Plate tectonics – theory that describes the surface of the Earth as comprised of large tectonic plates
  - Geophysics – physics of the Earth and its environment in space; also the study of the Earth using quantitative physical methods. Includes Earth's shape; its gravitational and magnetic fields; its internal structure and composition; its dynamics and their surface expression in plate tectonics, the generation of magmas, volcanism and rock formation.
  - Meteorology – study of the atmosphere, including study and forecasting of the weather.
    - Tornadoes – violently rotating columns of air that can produce extreme damage.
    - Tropical cyclones – storm systems characterized by a large low-pressure center and numerous thunderstorms that produce strong winds and heavy rain.
  - Oceanography – The study of the physical and biological aspects of the ocean.
- Physics – study of matter and its motion through spacetime, along with related concepts such as energy and force. More broadly, it is the general analysis of nature, conducted in order to understand how the universe behaves.
  - Acoustics – interdisciplinary science that deals with the study of all mechanical waves in gases, liquids, and solids including topics such as vibration, sound, ultrasound and infrasound.
  - Energy – scalar physical quantity that describes the amount of work that can be performed by a force. Energy is an attribute of objects and systems that is subject to a conservation law.
  - Fluid dynamics – subdiscipline of fluid mechanics that describes the flow of fluids (liquids and gases).
- Space science
  - Astronomy – study of celestial objects (such as stars, planets, comets, nebulae, star clusters and galaxies) and phenomena that originate outside the Earth's atmosphere (such as the cosmic background radiation).
    - Solar System – gravitationally bound system comprising the Sun and the objects that orbit it, either directly or indirectly. Where the Earth is located (the third planet orbiting the Sun).
      - Mercury – closest planet to the sun.
      - Venus – second closest planet to the sun. It is a terrestrial planet.
      - Earth – home of the human race, and 3rd planet closest to the sun. It is the only planet known to support life.
        Moon – astronomical object that orbits planet Earth, being Earth's only permanent natural satellite.
      - Mars – terrestrial planet. Fourth closest planet to the sun.
      - Jupiter – gas giant, and fifth planet from the sun.
      - Saturn – gas giant, famous for its rings, and sixth planet from the sun.
      - Uranus – ice giant, and seventh planet from the sun.
      - Neptune – ice giant. Eighth and furthest planet from the sun.
    - Black holes – mathematically defined region of spacetime exhibiting such a strong gravitational pull that no particle or electromagnetic radiation can escape from it.
    - Galaxies – gravitationally bound systems of stars, stellar remnants, interstellar gas, dust, and dark matter. Earth is located in the Milky Way galaxy.