Scientists Say

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

  1. Space

    Scientists Say: Gravity

    Gravity is a fundamental force that attracts objects with mass to other objects with mass. It decreases with distance.

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  2. Science & Society

    Scientists Say: Theory

    A theory is an explanation of how part of the world works. It’s one that’s been tested many times and in many ways.

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  3. Chemistry

    Scientists Say: Plastic

    Plastics are made of long polymer chains and can take on many shapes. Unfortunately, they stick around for a long time.

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  4. 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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  5. 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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  6. 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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  7. 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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  8. 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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  9. 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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  10. 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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  11. 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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  12. 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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