Scientists Say

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

  1. Health & Medicine

    Scientists Say: Nicotine

    Nicotine is an addictive substance found in tobacco plants. It's what makes it so difficult to quit smoking or vaping.

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  2. Chemistry

    Scientists Say: Bond

    In chemistry, this attachment between atoms forms because of the power of attraction. Chemical bonds make up every solid object on Earth.

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  3. Plants

    Scientists Say: Pollen

    Pollen is a mass of tiny reproductive cells. These grains combine with egg cells to form seeds — but on the way, they can make some people miserable.

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  4. Chemistry

    Scientists Say: Metal

    Metals are substances that can be elements, alloys or compounds. They all conduct heat and electricity and can be formed into different shapes.

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  5. Life

    Scientists Say: Genus

    A genus is a group of closely related species. It’s the first part of the two-part system called binomial nomenclature, used to name living things.

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  6. Chemistry

    Scientists Say: Alkaline

    Alkaline chemicals are basic — substances that produce hydroxide ions in solution.

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  7. Math

    Scientists Say: Pi

    Pi is the ratio of a circle’s circumference to its diameter. But some mathematicians say life would be easier if we used a different ratio instead.

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  8. Fossils

    Scientists Say: Dinosaur

    Dinosaurs emerged between 243 and 233 million years ago. While some died out 66 million years ago, others are still with us — birds.

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  9. Health & Medicine

    Scientists Say: Placebo

    In clinical trials, scientists often test a drug or procedure against a placebo — a treatment that has no effect — to find out how well their new treatment works.

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  10. Physics

    Scientists Say: Acceleration

    Acceleration is a change in velocity. That could mean a change in speed or in direction.

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  11. Physics

    Scientists Say: Radiation

    Radiation is the motion of energy through space as waves or particles.

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  12. Brain

    Scientists Say: Neuron

    Neurons are the foundational cells in the nervous system. They pass along and process information using electrical signals.

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