Science Notes Posts

The 'squared circle' or 'squaring the circle' is a 17th century alchemical glyph or symbol for the creation of the Philosopher's Stone. The Philosopher's Stone was supposed to be able to transmute base metals into gold and perhaps be an elixir of life. — Alchemy Definition Several definitions of alchemy exist. Originally, alchemy was an ancient tradition of sacred chemistry used to discern the spiritual and temporal nature of reality, its structure, laws, and functions. Alchemy is often considered a predecessor to the modern science of chemistry. The word alchemy comes from the Arabic […]

What Is Alchemy? Definition

This entry was posted on May 25, 2019 by Anne Helmenstine (updated on May 25, 2019)

A short example problem showing how to calculate the period of a simple pendulum.

Period of a Simple Pendulum Example Problem

This entry was posted on May 14, 2019 by Todd Helmenstine (updated on July 8, 2019)

Law of Cosines Example — Law of Cosines example problems showing how to derive the law and how to use it to find the lengths of the sides or angles of a triangle.

Law of Cosines Example Problem

This entry was posted on May 3, 2019 by Todd Helmenstine (updated on August 4, 2019)

The green and red light in the sky around the Paranal Observatory is airglow. (Y. Beletsky (LCO)/ESO) — It never gets truly dark at night because of an effect called airglow. Airglow is similar in color to the aurora, but you don’t have to visit a polar region to see it. While the aurora is light released by the interaction between magnetosphere and the solar wind, airglow is […]

What Is Airglow? Why the Night Sky Is Never Truly ...

This entry was posted on April 25, 2019 by Anne Helmenstine (updated on May 19, 2019)

In addition to the prestige of winning an event at the Olympics, the victor receives a gold medal. At one time, Olympic gold medals were real solid gold. However, the last time a solid gold medal was awarded was at the 1912 Stockholm Olympics. Modern Olympic gold medals are sterling […]

Are Olympic Gold Medals Real Gold?

This entry was posted on March 30, 2019 by Anne Helmenstine (updated on March 30, 2019)

Neon Green Periodic Table — This collection of neon colored periodic table wallpapers are a great way to have a dark themed wallpaper and include useful information.

Neon Colored Periodic Table Wallpapers

This entry was posted on March 18, 2019 by Todd Helmenstine (updated on March 18, 2019)