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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, June 21, 2020

What did Jan Ingenhousz discover about photosynthesis?
What did Jan Ingenhousz discover about photosynthesis?
Companion / Science
Chlorophyll pigment in chloroplasts within plant cells. Microscopic organelles photosynthesis green
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
Unusual Counting Systems
In everyday life we use a base-10 counting system, but that is not something that has always been used in history.
Spotlight / Science
bunch of numbers
Fast Facts about the Cell Membrane
Gate, gatekeeper, and protector.
List / Science
Cell transport - illustration of a diffusion of liquid molecules through cell membrane. Phospholibid bilayer
What’s the Difference Between Asian and African Elephants?
Three significant physical factors make it easy to distinguish these two types of proboscidean.
Demystified / Science
Asian and African elephant side by side
Physical science
Physical science, the systematic study of the inorganic world, as distinct from the study of the organic world, which is...
Encyclopedia / Science
The Compact Muon Solenoid magnet arriving in the Large Hadron Collider at CERN, 2007.
Climate change
Climate change, periodic modification of Earth’s climate brought about as a result of changes in the atmosphere as well as...
Encyclopedia / Science
Grinnell Glacier shrinkage
Climate
Climate, conditions of the atmosphere at a particular location over a long period of time; it is the long-term summation...
Encyclopedia / Science
A diagram shows the position of Earth at the beginning of each season in the Northern Hemisphere.

Science Quizzes

ten types of clouds and their elevation: cirrus, cirrocumulus, cirrostratus, altocumulus, altostratus, nimbostratus, stratocumulus, stratus, cumulus, cumulonimbus
Earth’s Atmosphere and Clouds
You may have heard of the car model, but is "stratus" a type of cloud? What do scientists call a cloud that does not carry...
Periodic table of the elements. Left column indicates the subshells that are being filled as atomic number Z increases. The body of the table shows element symbols and Z. analysis and measurement
Periodic Table of the Elements
What does the chemical symbol Ti represent? What is the symbol for magnesium? For iron? From the alkali metals to the noble...
A person's hand pouring blue fluid from a flask into a beaker. Chemistry, scientific experiments, science experiments, science demonstrations, scientific demonstrations.
Ins and Outs of Chemistry
You may know that elements make up the air we breathe and the water we drink, but do you know more about them? What element...
Water-ice clouds, polar ice, polar regions and geological features can be seen in this full-disk image of Mars.
Mars: Fact or Fiction?
From where does Mars get its name? Does the "Red Planet" experience dust storms? Travel beyond Earth and set foot on all...
Part of the laser system developed for the measurement of the proton radius. equency doubling optics converting the disk laser pulses from 1030 nm (infrared) to 515 nm (green) by means of LBO crystals.
Light: Fact or Fiction?
Does a laser amplify light? Can light therapy help people battle depression? Sort fact from fiction in this illuminating...
The word spring can be used for any elastic object that stores energy, such as a rubber band. Human hand aims red rubberband ready to shoot. Aiming, stored engergy
Energy and Fossil Fuels: Fact or Fiction?
When stretched, what type of energy does a rubber band store? Does walking up stairs use more energy than walking on level...
Water droplets on flat surface.
Water: Fact or Fiction?
Is rainwater the purest form of water? Is fresh water more acidic than salt water? Test how deep your water knowledge goes...
Major features of the ocean basins. World terrain map.
Earth: Fact or Fiction?
How many major oceans does Earth have? Does land cover 50 percent of the area of the Earth’s surface? Dig into this Earth...
KC-135 Stratotanker refueling U.S. Airforce military F-16 Falcon. Transportation aircraft refueled in mid-air aka aerial refueling.
Aircraft: Fact or Fiction?
Is the airline industry the world’s largest consumer of oil? Can Air Force One be refueled in mid-air? See if you’re fit...
Able (pictured here) an American-born rhesus monkey and Baker a South American squirrel monkey were launched in the nose cone of an Army Jupiter Missile May 28, 1959. Both were recovered unharmed. Baker lived to age 27, Able died June 1, 1959. NASA.
Space Navigation: Fact or Fiction?
Was a monkey the first animal in orbit? Was international spying the foundation of U.S. and Soviet space programs? Find out...
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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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