<option id="wfwem"></option>

<dd id="wfwem"></dd>
    1. You are using an outdated browser. Please upgrade your browser to improve your experience and security.


      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 28, 2020

      Are Chimpanzees Cannibals?
      Chimpanzees are usually herbivores, eating berries, fruits, leaves, and the occasional insect or egg. But could these friends...
      Companion / Science
      Mother and juvenile chimpanzees on a tree branch. Taken in the wild in Africa.
      What’s the Difference Between a Psychopath and a Sociopath? And How Do Both Differ from Narcissists?
      Know a mentally disturbed person who doesn’t think much of others? Make sure you apply the right epithet.
      Demystified / Science
      Obscure Freaky Smiling Psycho Man, phsychopath, sociopath, evil, mean
      Working Like a Dog: 7 Animals with Jobs
      Sit. Roll over. Diagnose this patient.
      List / Science
      Working German Shepherd dog sniffing a suspecting package for drugs or explosives.
      10 Deadly Animals that Fit in a Breadbox
      Tiny terrors of the animal kingdom.
      #WTFact / Science
      Mosquito on human skin.
      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, 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.
      Metabolism, the sum of the chemical reactions that take place within each cell of a living organism and that provide energy...
      Encyclopedia / Science
      mitochondria and cellular respiration
      Anthropocene Epoch
      Anthropocene Epoch, unofficial interval of geologic time, making up the third worldwide division of the Quaternary Period...
      Encyclopedia / Science
      Anthropocene Epoch

      Science Quizzes

      The ESO 3.6-metre telescope at La Silla, during observations in Chile. Milky Way galaxy in sky. (European Southern Observatory)
      Seeing Stars: Fact or Fiction?
      Are there twelve signs in the zodiac? Is Sirius the brightest star in the sky? Connect the dots in this astronomy quiz.
      NOAA satellite image of Hurricane Katrina taken onaugust 28, 2005. On August 28, 2005, Hurricane Katrina was in the Gulf of Mexico where it powered up to a Category 5 storm on the Saffir-Simpson hurricane scale packing winds estimated at 175 mph.
      Weather: Fact or Fiction?
      Is the center of a tropical storm called a window? Does a barometer measure temperature? See if your knowledge is clear skies...
      Sundial (time; clock; timepiece)
      The Sun: Fact or Fiction?
      Does the Earth revolve around the Sun once per month? Are sunspots hotter than the Sun’s surface? Turn up the heat in this...
      US Skylab space station in orbit. After the Apollo missions, the next major NASA venture was the Skylab manned earth satellite program. The orbiting laboratory was launched on May 14, 1973, and during the year three separate crewsof three men were sent up
      Space Travel: Fact or Fiction?
      Was Mariner 1 the first spacecraft to photograph Earth from the Moon? From space shuttles to space stations, navigate the...
      General Sherman, the world's tallest giant sequoia (Sequoiadendron giganteum), Sequoia National Park, California. (redwoods, forests, trees)
      Trees of the World: Fact or Fiction?
      Did trees evolve hundreds of millions of years ago? Are birch trees short-lived? Sort fact from fiction in this dendrology...
      Thermometer, measuring 0 degrees Celsius and 32 degrees Fahrenheit.
      Mathematics and Measurement: Fact or Fiction?
      Does the concept of zero come from Indian mathematics? Is a jiffy a unit of measurement? Measure your wits in this mathematics...
      bacterial cell, antibiotic resistance, prokaryotic cell
      Bacteria, Mold, and Lichen: Fact or Fiction?
      Is penicillin made of mold? Can fungi photosynthesize? Sort fact from fiction in this science quiz.
      Laboratory glassware (beakers)
      Chemistry Basics: Fact or Fiction?
      Does all matter have mass and density? Are there three classical states of matter? Sort fact from fiction—and liquids from...
      wave. ocean. Cresting ocean wave. Large sea waves. storm, hurricane, tropical cyclone
      Oceanic Mass: Fact or Fiction?
      Does the ocean ever stand still? Is most of the world’s salt found in oceans? Sort fact from fiction in this oceanography...
      Oil change. Chaging oil. Petrochemical. Carbon Dioxide, Fossil Fuel, Power Generation, Gasoline, Greenhouse Gas, Natural Oil, Pollution, petroleum, car
      Petroleum: Fact or Fiction?
      Is crude oil usually black? Is natural gas a kind of petroleum? Rev up your mental engines and get your juices pumping in...
      Image Gallery
      Never Miss a Day in History
      Sign up for daily fun facts about this day in history, updates, and special offers delivered right to your inbox.

      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.
      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.
      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).
      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.
      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.
      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.
      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.
      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.
      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.
      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.
      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.
      Get kids back-to-school ready with Expedition: Learn!
      Subscribe Today!