Scientists Say

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

  1. Life

    Scientists Say: Amphibian

    Amphibians are ectotherms that live dual lives — they start off in water, breathing with gills, and end up breathing air with lungs.

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  2. Chemistry

    Scientists say: Chemical

    A chemical is anything made of two or more atoms bonded together in a fixed structure. Chemicals make up the world around us.

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  3. Space

    Scientists Say: Asteroid, meteor and meteorite

    Asteroids, meteors and meteorites are all space rocks. But one is in orbit, another is in the atmosphere and the third is on the ground on Earth.

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  4. Health & Medicine

    Scientists Say: Vaccine

    Vaccines help the body develop immunity to a disease. They are biological mixtures that imitate a disease so the body can defend itself.

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  5. Agriculture

    Scientists Say: Carbohydrate

    Carbohydrates are molecules with carbon, oxygen and hydrogen. Animals break down these chemicals in food to get energy.

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  6. Space

    Scientists Say: Solar

    What do solar energy, the solar year and solar flares have in common? They’re all related to the sun.

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  7. Archaeology

    Scientists Say: Archaeology

    People leave things where they’ve been — old buildings, trash heaps and human skeletons. Archaeology is the study of those left-behind things.

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  8. Ecosystems

    Scientists Say: Deforestation

    Trees slurp up carbon dioxide and help keep our planet cool. But deforestation cuts those trees down in large numbers.

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  9. Physics

    Scientists Say: Microgravity

    Gravity is a force that brings objects together. But when those objects get far away, the force feels small. It feels like microgravity.

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  10. Chemistry

    Scientists Say: Atom

    An atom is the smallest possible piece of a chemical element.

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  11. Ecosystems

    Scientists Say: Prairie

    Prairies are flat, fertile grasslands in North America. They are their own unique ecosystem.

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  12. Tech

    Scientists Say: GPS

    A GPS system relies on satellites orbiting the planet, constantly sending signals back to receivers on Earth.

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