Resistors

[RockinRocket]

I opened up a Xicon and a 70s Iskra resistor being more or less the same size. The Xicon being 1 watt and the Iskra being 1/2 watt. Construction was different as the Xicon leads were basically caps that insert over the resistor while the Iskra lead goes straight into the resistor element.

So im left wondering was the Iskra just underrated in wattage? How can it be the same size. Carbon film and carbon film of the same size should be equal power handling wise?

Then I was reading this
http://www.explainthatstuff.com/resistors.html

Under the section "How does the size of a resistor affect its resistance?"
I might not be understanding part of this correctly. "so a fatter pipe will resist the water less than a thinner one and a shorter pipe will offer less resistance than a longer one"

Would a short fat resistor act differently than a long skinny resistor of the same type/wattage?

I know its usually accepted to most that resistors of the same type/wattage don't have tone but what about having a different mass of the same wattage? They must dissipate the heat differently and as we know heat changes the resistance.

[Malcolm Irving]

There are various types of resistor, but for metal film or carbon film, the resistance comes from a spiral track just under the surface, so the resistance just varies according to the length of that track and its breadth and thickness.
The wattage rating is how much power can be dissipated as heat before the resistor becomes too hot. The rate of dissipation of the heat depends on the surface area of the resistor (so bigger resistors can have a higher power rating) but also on the surface temperature. Some manufacturers are happy for their resistors to run at a higher temperature (because they believe the material of the resistor can stand it). Modern resistors can seem small for their power rating but they can run very hot.

[stretch2011]

It's all in material composition.