Scientists Say

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

  1. Life

    Scientists Say: Zooxanthellae

    Algae called zooxanthellae live in the tissue of coral and provide the coral with food and its color.

  2. Space

    Scientists Say: Galaxy

    A galaxy is a group of millions to billions of stars, plus a lot of dust and gas.

  3. Animals

    Scientists Say: Extinction

    When the last member of a species dies, it’s gone forever. That species is extinct.

  4. Chemistry

    Scientists Say: pH

    pH is a scale used to measure the acidity or alkalinity of a solution. The scale ranges from zero to 14, with seven as the perfect neutral middle.

  5. Scientists Say: Mineral

    Minerals are chemical elements or compounds that form repeating crystal structures. Quartz is a mineral. Table salt is, too.

  6. Health & Medicine

    Scientists Say: Olfactory

    Smell something? Thank your olfactory sense. Olfactory refers to anything having to do with smell.

  7. Animals

    Scientists Say: Hertz

    Frequency is how often something repeats over a period of time. Frequency is often measured in hertz, the number of times a cycle repeats each second.

  8. 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.

  9. Life

    Scientists Say: Mitosis

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

  10. 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.