The umbra is the innermost part of a shadow, where the light source is completely blocked by the occluding body.
There are three main types of mountains: volcanic, fold, and block. All three types are formed from plate tectonics: when portions of the Earth’s crust move, crumple, and dive. Compressional forces, isostatic uplift and intrusion of igneous matter forces surface rock upward, creating a landform higher than the surrounding features. The height of the feature […]
The word autumn comes from the ancient Etruscan root autu- and has within it connotations of the passing of the year. It was borrowed by the neighbouring Romans, and became the Latin word autumnus. After the Roman era the word continued to be used as the Old French word autompne (automne in modern French), and […]
The terms “mushroom” and “toadstool” go back centuries and were never precisely defined, nor was there consensus on application. The term “toadstool” was often, but not exclusively, applied to poisonous mushrooms or to those that have the classic umbrella-like cap-and-stem form. Between 1400 and 1600 AD, the terms tadstoles, frogstooles, frogge stoles, tadstooles, tode stoles, […]
The word “forest” comes from Middle English forest, from Old French forest (also forès) “forest, vast expanse covered by trees”; first introduced in English as the word for wild land set aside for hunting without the necessity in definition for the existence of trees (James 1981;Muir 2000,2008). Possibly a borrowing (probably via Frankish or Old […]