Scientists Say

A weekly word defined, in a sentence and in context.

  1. Physics

    Scientists Say: Big Bang

    The Big Bang is the current theory about how our universe came to be. It began with a vast explosion of matter — a very Big Bang.

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  2. Life

    Scientists Say: Mitosis

    Mitosis is a type of cell division where one cell divides into two identical copies, called daughter cells.

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  3. Animals

    Scientists Say: Hagfish

    Hagfish are eel-shaped fish with many traits that make them similar to long-vanished fossils. When threatened, they can pump out piles of slime.

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  4. Health & Medicine

    Scientists Say: Obesogens

    The chemicals can change how the body stores fat or how often someone feels hungry — increasing the risk for obesity.

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  5. Climate

    Scientists Say: Eyewall

    The calm center of a hurricane or other tropical cyclone is called the eye. But the worst winds and rain are around it, in the eyewall.

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  6. Chemistry

    Scientists Say: Ferrofluid

    Ferrofluids are liquids with tiny magnetic particles in them. These liquids respond to magnets.

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  7. Scientists Say: Naloxone

    This drug can save people who have overdosed on opioids, such as fentanyl and oxycodone.

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  8. Physics

    Scientists Say: Light pollution

    Light pollution is when artificial light shines into places that are normally dark. It can disrupt the lives of plants, animals and people.

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  9. Health & Medicine

    Scientists Say: Myopia

    Myopia is nearsightedness, where people have trouble seeing far away objects. This happens if someone’s eyes are slightly oval, instead of perfect spheres.

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  10. Health & Medicine

    Scientists Say: Neutrophil

    Neutrophils are the first cells to arrive when an infection takes hold. They can trap, eat and spew out chemicals that fight bad bacteria.

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  11. Animals

    Scientists Say: Guinea worm

    Scientists and health care workers are working to eradicate this parasite, which causes a painful condition called Guinea worm disease.

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  12. Space

    Scientists Say: Space weather

    It may not be cloudy with a chance of rain, but space has weather too. Wind and ejections from the sun can send charged particles toward the Earth, knocking out our electricity.

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