I'm not sure what's worse, the fact that Kevin posted about the proper way to load a toilet paper holder, or that I've been thinking about posting the same thing. Kevin proposes the "over" method where the loose bit of tissue falls over the top of the roll.
I respectfully disagree with Kevin, and I have proof of my conjecture. The proper way to load toilet paper is "under", and here's why:
A normal toilet paper roll has quite a bit of space inside the tube when loaded in the holder, as the dowel is not usually as big as the tube. (See Figure 1) This allows the roll to move back and forth when the tissue is being dispensed. This motion is different depending on how the roll is loaded.
Figure 2 illustrates what happens when force is applied to the roll in the "over" position. As the tissue is pulled down, the dowel in the holder acts as a fulcrum, and the roll is pressed downward and towards the wall. This causes friction between the tissue and the wall, which can add enough strain to cause the tissue to tear, leaving the user with less than required.
Figure 3 shows the "under" position, and illustrates why this method is superior. When pulling on the tissue in this position, the dowel acts as a fulcrum to pull the roll slightly upward and away from the wall, avoiding friction from the wall completely. This method allows the roll to spin freely, and the user is better able to control how much tissue to use and when to tear it.
The laws of physics clearly dictate that the proper way to load a roll of toilet paper is the "under" method. This gives the user more control over how much tissue they use, and reduces the stress and frustration caused by the continuous premature tearing of the tissue that the "over" method causes.
As you can see, the scientific proof is indisputable.