Scientists Say

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

  1. Chemistry

    Scientists Say: Electron

    Electrons are negatively charged particles. They are attracted to the positively charged particles in the center, or nucleus, of an atom.

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  2. Earth

    Scientists Say: Magma and lava

    The word magma refers to molten rock deep inside Earth. That rock is called lava when it reaches Earth’s surface.

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  3. Earth

    Scientists Say: Anthropocene

    Humans are changing the world in profound ways. Some scientists think those changes have launched a new epoch in Earth’s history: the Anthropocene.

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  4. Health & Medicine

    Scientists Say: Tonsils

    The tonsils are pads of tissue in the throat that are part of the body’s immune system.

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  5. Brain

    Scientists Say: Haptic

    Haptic is an adjective used to describe things related to our sense of touch.

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  6. Physics

    Scientists Say: Plasma

    In physics, plasma refers to one of the four states of matter. In medicine, plasma describes the part of blood that ferries cells, nutrients and more throughout the body.

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  7. Materials Science

    Scientists Say: Aerosol

    Aerosols are tiny bits of solids or drops of liquids suspended in gas. Aerosols include mist, fog and soot, as well as pollution from fossil fuels.

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  8. Chemistry

    Scientists Say: Oxidation and Reduction

    Oxidation and reduction are two parts of a chemical process in which one atom steals electrons from another.

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  9. Physics

    Scientists Say: Mass

    Mass shows how much an object resists speeding up or slowing down when force is applied — a measure of how much matter is in it.

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  10. 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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  11. 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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  12. 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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