Defining the end of female puberty. Discover the biological milestones—like skeletal maturity and stable hormones—that mark the transition to adulthood.
Explore the atomic mechanics that enable electricity to flow. Understand why specific metals are used and how resistance and insulation manage the current.
Discover the combined reasons for early winter darkness: Earth's axial tilt, the artificial shift of Daylight Saving Time, and the physics of twilight.