Develop a model that predicts and describes changes in particle motion, temperature, and state of a pure substance when thermal energy is added or removed.

  1. Health & Medicine

    Explainer: All about the calorie

    Calories are a measure of how much energy is in a food. But when it comes to powering our bodies, not all calories are equally available to the body.

  2. Chemistry

    Explainer: What is a catalyst?

    Catalysts are used in manufacturing and many technologies. They’re also found in living things. They help chemical reactions move along.

  3. Chemistry

    Here’s how hot water might freeze faster than cold

    There’s a new explanation for how hot water freezes faster than cold water. But not everyone agrees it’s right, or that the effect can happen at all.

  4. Physics

    Weird physics warps nearby star’s light

    Scientists have observed a bizarre effect of quantum physics in light coming from a nearby neutron star.

  5. Chemistry

    Scientists Say: Sublimation

    Matter doesn’t always go from solid to liquid to gas. Sometimes it skips a step.

  6. Teen studies better cleaning through chemistry

    Why do we use hot water and soap to get things clean? To find out, a teen invented a way to measure surface tension.

  7. Physics

    Scientists Say: Absolute zero

    Even when we think it’s cold out, most molecules are moving. Only at absolute zero will all of their motions stop.

  8. Physics

    Sunlight + gold = steaming water (no boiling needed)

    Nano-gold is the new black, at least when it comes to absorbing heat. When tiny gold particles get together, they become energy super-absorbers — turning them black.

  9. Earth

    Carbon dioxide could explain how geysers spout

    A new study overturns 150 years of thinking about Yellowstone’s geysers. Carbon dioxide, not just hot water, may be driving those spectacular eruptions.

  10. Tech

    Cool Jobs: Big future for super small science

    Scientists using nanotechnology grow super-small but very useful tubes with walls no more than a few carbon atoms thick. Find out why as we meet three scientists behind this huge new movement in nanoscience.

  11. Physics

    News Brief: As timely as it gets

    A newly modified atomic clock won’t lose or gain a second for 15 billion years. This timepiece is about three times more precise than an earlier version.

  12. Physics

    How popcorn got its pop

    Popcorn is a popular treat. Now, scientists have learned exactly what happens as it pops. They also have come up with an experiment they hope you will try.