Monday, July 20, 2009

"Full fathom five thy father lies;
Of his bones are coral made;
Those are pearls that were his eyes;
Nothing of him that doth fade,
But doth suffer a sea-change
Into something rich and strange..."

Ariel's Song to Ferdinand
The Tempest by
William Shakespeare


What is the difference between a physical change and a chemical change?


1. A physical change is reversible, a chemical change is not. For example, the freezing of water would be a physical change because it can be reversed, whereas the burning of wood is a chemical change - you can't 'unburn' it: physical change is a change in which no new substance is formed.

2. A chemical change is a change of materials into other, new materials with different properties, and one or more new substances are formed. Freezing water into ice just results in water molecules which are 'stuck' together - it's still H2O. Whereas burning wood results in ash, carbon dioxide, etc, all new substances which weren't there when you started.

But a chemical change hasn't changed or added to the atoms of the burned wood. It's still what it is, with the atoms forming new alliances or going it alone. Carbon was there in the wood before burning and is there after burning... in a different state, but still carbon.


Here's what happens with the pulling apart of atoms

A 23 kiloton tower shot called BADGER, fired on April 18, 1953 at the Nevada Test Site, as part of the Operation Upshot-Knothole nuclear test series.

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