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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.
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Featured content, May 28, 2020

Fightin’ Fauna: 6 Animals of War
Some battles were won with unexpected weapons.
List / Science
bird. pigeon. carrier pigeon or messenger pigeon, dove
Unidentified Flying Objects: What We Know
Everything we know (and only what we know) about the phenomenon of UFOs.
Companion / Science
Ufo, alien, space over trees.
Amazing Mangroves
Mangroves are much more than just odd tangled trees.
Spotlight / Science
Exposed roots of mangrove trees in Tha Pom Khlong Song Nam park, near Krabi, Thailand. Forest swamp habitat ecosystem plants
What’s the Difference Between a Meteoroid, a Meteor, and a Meteorite?
The difference between the three depends on where they are.
Demystified / Science
Meteor shower. Elements of this image furnished by NASA
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
Gedankenexperiment
Gedankenexperiment, (German: “thought experiment”) term used by German-born physicist Albert Einstein to describe his unique…
Encyclopedia / Science
Philosophy of science
Philosophy of science, the study, from a philosophical perspective, of the elements of scientific inquiry. This article discusses…
Encyclopedia / Science
Aristotle
Evolution
Evolution, theory in biology postulating that the various types of plants, animals, and other living things on Earth have…
Encyclopedia / Science
The geologic time scale from 650 million years ago to the present, showing major evolutionary events.

Science Quizzes

rain. Child in the rain, wearing a rain coat, under a yellow umbrella. April Showers weather climate rain storm water drops
April Showers to March’s Lions and Lambs
What is the hottest recorded temperature on Earth? What’s the coldest? Do you know what a biome is? Strap on your thinking…
ball bearing. Disassembled ball bearing. rotational friction Automobile Industry, Engineering, Industry, Machine Part, Metal Industry, Sphere, Steel, Wheel
Inventors and Inventions
Our earliest human ancestors invented the wheel, but who invented the ball bearing that reduces rotational friction? Let…
NASA's Reduced Gravity Program provides the unique weightless or zero-G environment of space flight for testing and training of human and hardware reactions. NASA used the turbojet KC-135A to run these parabolic flights from 1963 to 2004.
Man-Made Birds in the Sky
From zeppelins to jet-powered propellers, launch into this quiz and test your knowledge of aircraft and aviation.
Rafflesiaceae. rafflesia. Rafflesia arnoldii, Malpighiales order, on the Island of Borneo. largest known flower in the world grows to aprox. 3 feet. Also known as the monster flower. Exudes a decaying flesh odor that attracts carrion flies.
Flowers: Nature’s Color Palette
You may know that honey is produced from the nectar of flowers, but what is the name of the world’s largest flower? What…
cigar. cigars. Hand-rolled cigars. Cigar manufacturing. Tobacco roller. Tobacco leaves, Tobacco leaf
Building Blocks of Everyday Objects
What are cigars made of? What material is glass classified as? See what you’re really made of by dissecting the questions…
Italian-born physicist Dr. Enrico Fermi draws a diagram at a blackboard with mathematical equations. circa 1950.
Physics and Natural Law
What force slows motion? For every action there is an equal and opposite what? There’s nothing E = mc square about taking…
barometer. Antique Barometer with readout. Technology measurement, mathematics, measure atmospheric pressure
Fun Facts of Measurement & Math
What does a barometer measure? During which year do humans grow the fastest? Gather your wits and measure your knowledge…
Saturn. Saturn and its rings. Second largest planet of the solar system. Space Art
Planets and the Earth’s Moon
What’s the relationship between distant planets and supposed extraterrestrial life? What is our solar system’s hottest planet?…
battery. Illustration of battery connected to lightbulb. Power a light bulb with a battery. Battery, Power Supply, Science, Circuit, Currents
Electricity: Short Circuits & Direct Currents
What’s the difference between an electrical conductor and an insulator? Who invented the battery? Feel your cells burn as…
White semi truck on the Highway. Truck, lorry, motor vehicle to carry freight or goods or perform special services. Cab, carrier, semis trucks.
Machinery and Manufacturing
From drilling holes and moving freight to car engines and their production, tinker with these questions and test your knowledge…
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
An illustration of the difference between average and instantaneous rates of changeThe graph of f(t) shows the secant between (t, f(t)) and (t + h, f(t + h)) and the tangent to f(t) at t. As the time interval  h approaches zero, the secant (average speed) approaches the tangent (actual, or instantaneous, speed) at (t, f(t)). 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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