The video “Variations in Plant Traits” explains how the natural environment causes variations in plant traits.

Howcast - Learn how to do a heelside check slide from competitive skateboarder Nate Cohen in this Howcast skateboarding video.

The simplest definition of free will is the ability to have made a different choice. Our more precise definition: it is the ability of conscious beings to make choices that are not solely determined by prior physical...

We just learned about electron microscopy, so what was the next major innovation in microscopy in the 20th century? That would be fluorescence microscopy, of both the widefield and confocal varieties. How does this work? What is...

A neutron star is a rotating, superdense, dead star. A pulsar is a type of neutron star that must be both magnetized and moving very fast, because it spins its magnetic field fast enough to produce a beam of electromagnetic radiation....