Matter and Its Interactions

  1. Physics

    Explainer: What is friction?

    The force of friction always acts to slow things down. It depends on just two factors: the surfaces and how hard they press together.

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  2. Physics

    Explainer: Radiation and radioactive decay

    Like clockwork, radioactive forms of some elements shed parts of themselves as they attempt to become nonradioactive.

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  3. Physics

    Explainer: Radioactive dating helps solve mysteries

    Knowing the decay rate of radioactive elements can help date ancient fossils and other artifacts.

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  4. Tech

    A tool as small as a human cell can scan for contaminants and more

    Tiny spectrometers might someday show up on smart devices. They could help people scan for ingredients or contaminants in foods and other materials.

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  5. Chemistry

    Scientists Say: Fluorescence

    This property causes materials — including some animals’ skin, fur or feathers — to glow under light.

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  6. Environment

    This chemist uses online videos to teach about the perils of microplastics

    Imari Walker says her journey as a scientist and science communicator lets her talk about and advocate for her passion.

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  7. Environment

    Bacterial ‘living wires’ could help protect the seas and climate

    Long, thin bacteria that conduct electricity may be able to help clean up oil spills and reduce emissions of methane, a powerful greenhouse gas.

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  8. Physics

    Protons may be stretchier than physicists had thought

    Physicists looked at how the quarks that make up protons move in response to electric fields. And they found more movement than expected.

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  9. Chemistry

    Explainer: What is a hydrogel?

    These unusual materials have a host of unusual properties. You can even make a starch-infused version in your kitchen.

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  10. Environment

    ‘Forever’ chemicals show up in students’ school uniforms

    Researchers found PFAS “forever chemicals” in kids’ school uniforms and other clothing. Studies have linked these compounds to health risks.

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  11. Materials Science

    Let’s learn about microplastics

    Microplastics have turned up everywhere from the highest mountains to the bottom of the ocean — and even inside animals and people.

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  12. Tech

    A shape-shifting robotic tooth-cleaner might one day brush for you

    A swarm of billions of magnetic, bacteria-killing nanoparticles can be shaped into bristles to fit any surface, including between teeth.

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