Out of your pennies, try to find the dirtiest one.
Take a small piece of paper towel and dampen it slightly with water.
With as much effort as you can, try for about 30 seconds to polish the penny with the paper towel. Is anything happening?
Now, take the pencil's eraser and try to "erase" the patina covering the penny. What's happening now, and why?
Hmm... it seems nobody's added a conclusion for this experiment yet. You can suggest one here.
In seahorses, it's the male that carries the babies and eventually gives birth.