I will conclude my "Obvious Differences" category with a brief discussion about Electricity.

Poland, along with most if not all of Europe, follows much closer to Nikola Tesla’s standard for electrical distribution at 230 Volts and 50 Hertz.  Whereas the United States follows Thomas Edison’s standard at 120 Volts and 60 Hertz. 

The result of this, is that you need to have a voltage adapter capable of handling the additional voltage.  For most modern electronics and computer equipment, this isn’t a problem.  Most desktop computers have a switch on the back to select the voltage.  

If there is no converter built in, or the power supply can’t handle the voltage, you need an external voltage converter…  These are usually good for short term usage only, and can burn out with long term use, or low-wattage equipment like computers.

Each system has it’s advantages and disadvantages.  If you’re really interested, read more about it:

http://en.wikipedia.org/wiki/War_of_Currents

http://science.howstuffworks.com/electricity.htm

The other major difference is the sockets themselves.  In the US we have a two or three prong plug where the two main prongs are flat (sometimes one is larger than the other – usually in any equipment where polarity is important).  The third prong is the ground, and is usually round (ish).  The socket has two or three corresponding holes, and both the socket and plug are typically shaped like an oval, with the long sides flattened out.

In Poland, the plug has two prongs and one hole.  The prongs are round, as is the hole.  The hole is for ground, and the prong for this is actually on the socket.  The socket has two holes, which typically have some kind of spring-loaded plastic covers which cover the holes – I’m guessing for safety reasons.  The plug and socket are both circular, which tends to make them feel a bit bulky.  Though most non-grounded plugs are small and diamond shaped, having only the two prongs and they slide in next to the round prong.

I took a picture of a socket, but oddly enough, forgot to get one of the plug.

Another difference related to, but not directly influenced by electricity is the light switches.  

This doesn’t exactly fall into the "Obvious differences" category, but I figured as long as I was on the topic…

In the US we have switches where we’re actually toggling a little bar up and down…  In Poland the switches are much bigger and work with more of a see-saw action.  See the picture: