Upgrade your account to a Community Supporter account and remove most of the site ads.

Reply to thread

Message: <blockquote data-quote="Pyrex" data-source="post: 3288140" data-attributes="member: 11600">Because in the case of the city, the box isn't full.  The inhabitants have to breathe.Assuming the city is 2 mi^2 in area, roughly circular, And that the Walls of Force surrounding/covering the city are roughly* dome-shaped, the volume of the enclosed area contains massive amounts of air**.  Since saturated wet sand has a density approaching that of stone, the dome of force only needs to extend, say 15' above any building in the city to lower the average density of the city enough (unless they did something odd like build the foundation of the city out of lead) to float it to the surface.Granted, the whole city isn't going to be floating at the surface unless you place hundreds of tons of low-density material under the foundation, but once the top 20' or so is exposed to air that's good enough to get started.*With a diameter of over a mile, the dome obviously isn't a perfect hemisphere; if it was you could hardly consider the city "buried" <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f600.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":D" title="Big grin    :D"  data-smilie="8"data-shortname=":D" />**Maintaining air quality in an airtight large city is a whole 'nother thread... <img src="https://cdn.jsdelivr.net/joypixels/assets/8.0/png/unicode/64/1f61b.png" class="smilie smilie--emoji" loading="lazy" width="64" height="64" alt=":p" title="Stick out tongue    :p"  data-smilie="7"data-shortname=":p" />It's not about area, it's about density.  If the average density of the city is less than the average density of the surrounding medium, it'll float.  The greater the difference the faster it'll float.Solid Granite is 2691 times as dense as water, so you'd need 3 10x10x10' cubes of force enclosing 1ft^3 of granite to float it; meaning you'd need a massive dome of force to float a city mostly constructed of stone.Wet Sand has a density <a href="http://www.simetric.co.uk/si_materials.htm" target="_blank">1922</a> times that of water, which is well over half the density of solid granite.  Which means that even if the Wall of Force is skimming the rooftops, the air in and around the buildings is more than enough to float the city in wet sand.Machiavelli is probably right though.  Once you've got the sand good and saturated you'd probably need some Earthquake spells to shake it up enough to act like a liquid.</blockquote>

Verification