ludzkie-ciekawostki: Symmetry

Evidence: 100 • authority: 72

In everyday life, symmetry (from Ancient Greek συμμετρία (summetría) 'agreement in dimensions, due proportion, arrangement') refers to a sense of harmonious and beautiful proportion and balance. In mathematics, the term has a more precise definition and is usually used to refer to an object that is invariant under some transformations, such as translation, reflection, rotation, or scaling. Although these two meanings of the word can sometimes be told apart, they are intricately related, and hence are discussed together in this article. Mathematical symmetry may be observed with respect to the passage of time; as a spatial relationship; through geometric transformations; through other kinds…

Evidence: 38 • authority: 80

Preface: Always Together, Always Told Apart

Evidence: 38 • authority: 88

Mining Word Meanings. Quick now, what's your knee-jerk advice when your child is reading and he asks you the definition of a tough word he can't figure out? "Look it up in a dictionary," right? It's bad advice. It's particularly bad advice for developing readers struggling through a thorny selection and trying to make sense of it. Don't get me wrong—I have nothing against dictionaries. I love dictionaries. They are indispensable language- learning, language-checking tools. Writers, always aiming for precision amid perplexing word choices, could not survive long without dictionaries. For readers, too, dictionaries are important, but not in the ways we typically advise children to use them. C…