Enlighten the unenlightened here for a second...<p>Why would you even <i>want</i> to explain higher-order dimensions to a 5 year old?<p>I don't know all that many 5 year olds, in all honesty, but I don't know that I know ANY of them that I'd ever need to explain multi-dimensional space-time (or multi-dimensional mathematics, depending on what you want to call a "dimension").<p>C'mon, the kid's still very new to the world. They're barely comfortable with three dimensions at this point in their lives.<p>I understand that this question may have been posed simply as a rubber duck scenario, but even still, that'd be my first response.