I have a friend just getting into bass fishing. Regarding rods he asked me the difference between the power of a rod versus it's action. I kind of feel I understand the difference but am having trouble putting it into words. Also if two rods had no writing on them telling you their specs how would you compare the power/action of them to each other?

Here’s the most concise description I’ve ever seen. Couldn’t put it better myself. The library here is a wealth of information and imo underutilized. 
 

https://www.bassresource.com/fishing/rod-actions-power.html

 

 

Power is the thickness of the rod. Action is how quickly it goes from thin at the tip to thick at the butt, and how quickly it hits the "backbone" of the rod.

 

When you see heavy power and light power, heavy is going to be thicker than light, meaning it will bend less with a given load, so it is better for big fish or pulling through weeds. Match the power to the weight of the lure you're throwing, the size of fish you are targeting, and the level of vegetation you expect to encounter. For most bass fishing, a medium heavy power is a happy middle ground for your average 3/8 to 3/4oz jigs and moving baits, but if you are hitting thick vegetation, more power is needed to rip your lure free from those weeds and/or drag fish through them.

 

An extra-fast action means the taper of the rod blank goes from thin to thick very quickly, so you hit the backbone quickly. XF actions are often good for jigs because of the easy visibility of tip deflection change (when a fish bites, picks up the lure, etc). It is good for quick hooksets without as much of a yank on the rod. A moderate (slow) action means the rod more slowly transitions to the backbone and is good for moving baits, often with treble hooks, as you want to give the fish time to get hooked and not pull the hooks out of their mouth. You perform more of a "sweep" hookset with these, rather than a jerk or rip on the rod.

 

You cannot say something like "heavy action". It would "heavy power, X action". A lot of people make this mistake... I've seen 20+ year fishing veterans say it. I don't know why, unless it's just a slip-up.

 

Hopefully this helps!

 

 

2 minutes ago, bwjay said:

You cannot say something like "heavy action". It would "heavy power, X action". A lot of people make this mistake... I've seen 20+ year fishing veterans say it. I don't know why, unless it's just a slip-up.

   Many years ago, terminology was different. Where we now use "power/action" the old-timers would use "action/speed". That's where the "slow/fast/extra fast" in our M/S, M/F and M/XF come from. So they'd walk into a store and ask to see a "medium heavy action, fast speed" rod.

   I'm very aware that times change. I told a guy one time that I "had hit the foot-feed", and he stared at me uncomprehendingly. He'd never heard the term before.

 

   I'm not old.    ?    jj

31 minutes ago, Delaware Valley Tackle said:

Here’s the most concise description I’ve ever seen. Couldn’t put it better myself.

https://www.bassresource.com/fishing/rod-actions-power.html

Yep and for the TL;DR crowd: "Action refers to rod flex and Power refers the rod's resistance to flexing."

1 hour ago, michael1 said:

I have a friend just getting into bass fishing. Regarding rods he asked me the difference between the power of a rod versus it's action. I kind of feel I understand the difference but am having trouble putting it into words. Also if two rods had no writing on them telling you their specs how would you compare the power/action of them to each other?

Start with two tall glasses of bourbon don’t say anything till he’s half done. Then it will all start to make sense.