# Urinal 101

**URL:** <https://boards.straightdope.com/t/urinal-101/596346>\
**Category:** Cecil's Columns/Staff Reports\
**Created:** [September 15, 2011, 12:21am UTC](https://boards.straightdope.com/t/urinal-101/596346 "2011-09-15T00:21:46Z")\
**Posts on this page:** 2\
**Page:** 1

<div class="post-metadata">

**Author:** ![mathius\_dragoon](https://avatars.discourse-cdn.com/v4/letter/m/c67d28/32.png) [@mathius\_dragoon](https://boards.straightdope.com/u/mathius_dragoon)\
**Post date:** [September 15, 2011, 12:21am UTC](https://boards.straightdope.com/t/urinal-101/596346/1 "2011-09-15T00:21:46Z")

</div>

Referring to this column: [http://www.straightdope.com/columns/read/2450/urinal-101-aim-for-the-back-wall-or-the-water](http://www.straightdope.com/columns/read/2450/urinal-101-aim-for-the-back-wall-or-the-water)

Anybody who has had a lick of materials science classes should see the obvious problem with urinals. Lets list a few facts:

1. Urinals tend to be made out of porcelain
2. Porcelain is a type of ceramic
3. The most obvious property of ceramics, besides being fragile is that they are extremely hard. In fact they tend to be harder then metals.
4. Remember the billiard ball examples in physics class? The harder an object is the more inelastic it tends to behave in collisions.
5. In an inelastic collision, the total sum of the kinetic energy of the system doesn’t change.
6. Since urinals, by and large don’t seem to accelerate before my eyes, it is clear that all (or almost all as nothing is perfectly inelastic) of the kinetic energy of the urine is conserved, so you get the lovely experience of ricochet.

---

<div class="post-metadata">

**Author:** ![Powers](https://avatars.discourse-cdn.com/v4/letter/p/edb3f5/32.png) [@Powers](https://boards.straightdope.com/u/Powers)\
**Post date:** [September 15, 2011, 1:58am UTC](https://boards.straightdope.com/t/urinal-101/596346/2 "2011-09-15T01:58:09Z")

</div>

So you think a rubber urinal would be better?  
Powers &8^]