This Friday at www.talkingscience.org we will tackle that classic kid’s question of what makes the sky blue. Before we do however, let’s take a closer look at the word sky. Sky comes from the early 13 century Old Norse word skiuja for ‘a cloud’. Skiuja (also skeujam) was related to the Indo-European bases skuggi (shadow), skuggwa (mirror) and (s)keu- to cover or conceal. Clearly when early...
thixotropy This is a word you can actually trot out at a party: thixotropic. It comes from Ancient Greek: thixis from thinganein meaning to touch and tropos meaning to change. Matter exhibiting thixotropy changes when you touch it. Ketchup, a hydrocolloid composed of water and tomato particles (and a few other secret ingredients) is mostly a liquid. Leave it in the jar and it will settle to the...