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Science

How can the sky be blue one day and stormy the next? Why do heavy objects tend to fall downwards when dropped? How are birds able to fly (and why can’t I do the same?)? Human beings have long been curious about the world in which we live, striving to identify connections among the phenomenons we witness and to understand how it all works. The field of science has developed over many centuries as a way of studying and understanding the world, beginning with the primitive stage of simply noting important regularities in nature and continuing through the rise of modern science. The modern-day sciences cover a vast range of fields, including biology, chemistry, meteorology, astronomy, physics, and much more.
Browse Subcategories

Featured content, September 22, 2020

How Albert Einstein Developed the Theory of General Relativity
Learn how one of history’s greatest minds came up with one of science’s most important theories.
Companion / Science
Albert Einstein
7 Important Dates in Mercury History
A brief history of the first planet from the Sun.
List / Science
Planet Mercury photographed by the MESSENGER spacecraft. Colors produced by images from color base map imaging. Colors are not what Mercury looks to human eye. See NOTES:
Vikings Helped Cats Conquer the World
A genetic study indicates that cats spread across the globe thanks to Vikings and farmers.
#WTFact / Science
Norwegian forest cat relaxing in a tree
What's the Difference Between Speed and Velocity?
Not uncommonly, we hear these terms used interchangeably. So, what’s the difference?
Demystified / Science
Highway Night Traffic Portland, drive, driving, car, automobile.
Science
Science, any system of knowledge that is concerned with the physical world and its phenomena and that entails unbiased observations...
Encyclopedia / Science
Natural experiment
Natural experiment, observational study in which an event or a situation that allows for the random or seemingly random assignment...
Encyclopedia / Science
Scientific Revolution
Scientific Revolution, drastic change in scientific thought that took place during the 16th and 17th centuries. A new view...
Encyclopedia / Science
Copernican system
History of science
History of science, the development of science over time. On the simplest level, science is knowledge of the world of nature....
Encyclopedia / Science
Earth's Place in the Universe. Introduction: The History of the Solar System. Aristotle's Philosophical Universe. Ptolemy's Geocentric Cosmos. Copernicus' Heliocentric System. Kepler's Laws of Planetary Motion.

Science Quizzes

Group of horses. Herd of running Horses in Colorado, Western United States of America. Animal, running, horsemeat, horse meat.
Thereby Hangs a Tail: Famous Horses
Can you identify these well-known horses?
Thunderstorm cumulonimbus clouds above Montana. weather storm thunderstorm atmospheric disturbance cumulonimbus clouds thunder and lightning Homepage blog 2011, science and technology
Clouds and Cloud Types
Think you know every cloud type? Test your knowledge with this quiz.
American alligator hatchling. (endangered species; reptile; baby animal; reptile egg; animal birth; hatching)
About to Pop: How Many Babies?
How many babies does a fox typically have? What about a tiger? Test your knowledge of animal reproductive rates.
A lion (Panthera leo) eating its prey.
Pounds of Flesh: How Much Can They Eat?
When you don’t know when your next meal might walk by, portion control doesn’t apply. Test your knowledge of how much these...
Blueberries (Vaccinium) in a bowl. Fruit berry
Tasty Taxonomy
How well do you know the taxonomy of the plants you eat?
Edwin E. Aldrin (Buzz Aldrin) stands on the moon, Apollo 11
Famous Astronauts and Cosmonauts
Test your knowledge of those who had the right stuff to travel into space.
Chutes d'Ekom - a waterfall on the Nkam river in the rainforest near Melong, in the western highlands of Cameroon in Africa.
Ecosystems
There are a lot of ecosystems in the world. How much do you know about the different types of ecosystems?
Manure, a mixture of animal excrement and straw, sits in a pile in a field in France.
All About Poop
Know a thing or two about number two? Squeeze this quiz in before you eat.
Cute kitten and puppy (labrador) outdoors in the grass. Two different furry mammals have three kinds of hair: guard hairs, whiskers and soft underhairs. cat and dog, animal friends, funny young pets. Same as asset 166986/ic code pet000014, different right
Canines vs. Felines
Do you think you can tell canines and felines apart? Test your knowledge with this quiz.
The Space Shuttle Columbia soars from Launch Pad 39A on July 1 1997 to begin the 16-day STS-94 Microgravity Science Laboratory-1 (MSL-1) mission.
Space Records
Have you got the right stuff? Show what you know about the many interesting records set in crewed spaceflight.
Image Gallery
Science
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Science Subcategories

subcategory placeholder Astronomy
Human beings have always been fascinated by the celestial sphere above, whose twinkling lights have inspired many theories and artistic endeavors. Study of the solar system has provoked more than just peaceful meditation, however; a major controversy among astronomers arose in the 16th century when Copernicus publicly championed heliocentrism, a Sun-centric model of the solar system that was in direct opposition to Ptolemy's Earth-centered model, which had been generally accepted from the 2nd century CE onward. But humankind's fascination with the world beyond Earth has also led to some landmark moments in history, as when space exploration took a giant step forward with the advent of technology that allowed humans to travel to the Moon and to build spacecraft capable of exploring the rest of the solar system and beyond.
Articles
Chordate Biology
If it’s alive, biology will define it, study it, observe all its functions, follow its vital processes, and interact with it, all in order to understand the life that animates it. In one of biology's best-known examples of such studious investigation, Charles Darwin came up with his scientific theory of evolution by natural selection after systematically observing a variety of plants and animals; his work acted as the foundation upon which modern evolutionary theory is built. But biology’s principles also operate within a plethora of other related fields, including biochemistry, biomedicine, biophysics, and microbiology.
Articles
Black girdle-tailed lizard (Cordylus nigra). Birds, Reptiles & Other Vertebrates
Although it can be hard to imagine that a peacock and a crocodile have much of anything in common, these animals are actually descendants of the same prehistoric vertebrates. Birds are thought to have descended from carnivorous dinosaurs that began growing feathers by the Late Jurassic Period; thus, birds are technically one lineage of reptiles. This evolutionary link highlights the way in which seemingly incongruous creatures can, in fact, share a common ancestor (though that doesn't mean that we should expect waterfowl and crocodiles to become friends anytime soon).
Articles
Mantid (Mantis religiosa). Bugs, Mollusks & Other Invertebrates
Some insects are so displeasing to humans that the word "bug" has come to be used as a verb meaning "to bother or annoy." Yet, in addition to being critically important—because they naturally recycle decaying matter—in maintaining balance within the food chain, bugs can also be fascinating creatures, whether in regard to the water strider's ability to run across the surface of water or in regard to assassin bugs' varied and creative means of catching and killing their prey. Mollusks, another group of invertebrates, get less of a bad rap. Their ranks include nearly 100,000 described species of soft-bodied animals that are usually wholly or partly enclosed in a calcium carbonate shell; examples include snails, clams, oysters, squids, and octopuses.
Articles
periodic table Chemistry
How do you use raw plant materials to manufacture a best-selling perfume? How do you engineer household products that are compliant with environmentally-oriented guidelines? The answers to these questions require an understanding of the laws of chemistry, the science that deals with the properties, composition, and structure of elements and compounds, as well as the transformations that such substances undergo and the energy that is released or absorbed during those processes. Chemistry is also concerned with the utilization of natural substances and the creation of artificial ones. Over time, more than 8,000,000 different chemical substances, both natural and artificial, have been characterized and produced. Chemistry's vast scope comprises organic, inorganic, physical, analytical, and industrial chemistry, along with biochemistry, environmental chemistry, medicinal chemistry, and much more. Through the dedicated efforts of people such as Robert Boyle, Dmitri Mendeleev, John Dalton, Marie Curie, and Rosalind Franklin, the field of chemistry has led to exciting innovations as well as crucial advances in our understanding of how the world functions, starting with just the miniscule and unassuming atom.
Articles
subcategory placeholder Earth Science, Geologic Time & Fossils
Planet Earth has billions of years of history, from the time when it was an inhospitable ball of hot magma to when its surface stabilized into a variety of beautiful and diverse zones capable of supporting many life-forms. Many are the species that lived through the various geologic eras and left a trace of their existence in the fossils that we study today. But Earth is never done settling, as we can see from the earthquakes, tsunamis, volcanic eruptions, and other phenomena manifested in Earth’s crust, oceans, and atmosphere.
Articles
Grinnell Glacier shrinkage Environment
Biological diversity is key to a healthy ecosystem, whether it’s a small biological community or the global biosphere. Ecology, which studies the relationships between organisms and their environment, is an invaluable science that helps us understand what allows an ecological community to thrive.
Articles
Meerkat, or suricate (Suricata suricatta). Mammals
These are the animals to which humans tend to relate the most, perhaps because aspects of their behavior can sometimes resemble the way that we ourselves behave. The protective instinct of a mother bear, the gamboling way that kittens play, and the loyalty displayed by a dog are all traits that we can identify with in the course of our own lives. Mammals are well-equipped to handle different climates and biomes because of their ability to regulate their own body temperatures and internal environment, both in excessive heat and aridity and in severe cold.
Articles
Plot of the cubic equation f(x) = x3 ? 3x + 2. The plotted points are where changes in curvature occur. Mathematics
Although stock portrayals of mathematicians often involve a studious person standing in front of a chalkboard that's covered with mind-bogglingly complex scrawled mathematical problems (call it the "Good Will Hunting" effect), the chaotic-looking equations may obscure the fact that mathematics is, at its heart, a science of structure, order, and relation that deals with logical reasoning and quantitative calculation. There's a method to all that madness! The history of mathematics can be traced back to ancient Mesopotamia, whose clay tablets revealed that the level of mathematical competence was already high as early as roughly the 18th century BCE. Over the centuries, mathematics has evolved from elemental practices of counting, measuring, and describing the shapes of objects into a crucial adjunct to the physical sciences and technology.
Articles
mandacaru cactus Plants
Life on Earth owes much to plants. The vast majority of plants carry out photosynthesis to transform light energy into chemical energy, which is the way that virtually all energy in the biosphere becomes available to living things (including us humans). As photosynthetic organisms, plants occupy the base of Earth's food webs and are consumed directly or indirectly by all higher life-forms, thereby functioning as the major source of food for humans and other animals. Plants' photosynthetic activity also produces the air that we breathe: almost all the oxygen in the atmosphere is due to the process of photosynthesis. Still not convinced about the merits of plants? Consider the fact that many plants not only serve up crucial nutrients and breathable air but also look good doing it. Many plants are admired for their striking aesthetic qualities, and flowers such as tulips, lilies, sunflowers, and daisies beautify fields, gardens, windowsills, and bouquets the world over. Plants are also a primary source of consumer goods, such as building materials, textile fibers, and pharmaceuticals.
Articles
Acoustics Physics
What’s the matter? The matter is our whole observable universe—with that material substance that constitutes it—and it is the subject of study of physics. The laws that govern motion observed by Newton, the gravitational force that regulates the progress of all celestial bodies, the interaction between subatomic particles, and the nuclear engineering that created the atomic bomb are examples of what this important discipline is all about. Minkowski’s space-time concept, which reformulated Einstein’s special theory of relativity, has bridged physics with philosophy in a conversation that has fascinated the modern concept of physics.
Articles
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