Learn about refraction in physics. Get its definition and explore Snell's law and the index of refraction. Get examples for light and sound. Refraction – Definition, Refractive Index, Snell’s Law This entry was posted on October 20, 2021 by Anne Helmenstine (updated on October 25, 2021)
Turn water into liquid gold with this classic alchemy experiment that makes sparkling orpiment crystals appear from a clear solution. Water Into Liquid Gold Alchemy Experiment This entry was posted on October 19, 2021 by Anne Helmenstine (updated on June 30, 2026)
The copper and nitric acid chemistry demonstration is a dramatic color change chemical reaction. See how to do it safely. Copper and Nitric Acid Chemistry Demonstration This entry was posted on October 17, 2021 by Anne Helmenstine (updated on November 7, 2023)
Get the freezing point depression formula and definition. See how you calculate it and get examples in everyday life. Freezing Point Depression Formula and Definition This entry was posted on October 16, 2021 by Anne Helmenstine (updated on April 7, 2026)
See how to choose a telescope. Learn the difference between reflectors vs refractors, types of mounts, and other factors you should consider. How to Choose a Telescope – Reflector vs Refractor This entry was posted on October 14, 2021 by Anne Helmenstine (updated on November 5, 2025)
Learn about ionic equations. See the difference and examples of the molecular, complete, and net ionic equation. Net Ionic Equation and Complete Ionic Equation This entry was posted on October 13, 2021 by Anne Helmenstine (updated on October 18, 2021)
Learn the rules for naming ionic compounds and get examples of binary compound and polyatomic compound names. Naming Ionic Compounds – Nomenclature Rules This entry was posted on October 12, 2021 by Anne Helmenstine (updated on March 8, 2022)
Learn what a desiccant is in chemistry. Get the definition and examples of desiccants found in the home, lab, and workplace. What Is a Desiccant? Definition and Examples This entry was posted on October 10, 2021 by Anne Helmenstine (updated on May 9, 2026)
Learn about hand warmer chemistry and get instructions for four easy chemical hot packs. Learn how chemical hand warmers work. Hand Warmer Chemistry – Easy Chemical Hot Packs This entry was posted on October 9, 2021 by Anne Helmenstine (updated on January 3, 2023)