Site Glossary

A straight line matching a curve’s instantaneous slope at a point.

Instantaneous velocity directed tangent to a circular path.

A cell that has receptors for a specific hormone.

possible evidence of technological activity.

The stage when two new nuclei form.

A transmission electron microscope that passes electrons through a thin specimen.

A measure of how hot a star's surface is.

A force along the length of a medium, for example, the force in a rope that is exerted on another body.

Constant falling velocity reached when drag balances weight.

Male organs that produce sperm and testosterone.