Hi, Kathy,
To confirm what everyone else has told you, yes, you'll need an adapter. British electrical outlets are three pronged, and incompatible with anything you'll find in the U.S. If the electrical items that you are bringing to Scotland will work on both 110 and 220/240 volts, then an adapter is all you'll need. That would work for things like battery chargers. However, if you're bringing something like a hair dryer, then you'll definitely need a converter. Expect to pay at least $30.00 for a converter. If you're paying less, it's probably just an adapter.
Because of the circuitry need to convert 110 v to 220/240 v, your converter is going to weigh about a pound. I have an old Franzus converter which I bought about 30 years ago, and I've loaned it to friends who have traveled all over the world. It hasn't fried anything yet, so my friends are still friends!
If anything that you're bringing to Scotland has a three pronged electrical cord (two standard prongs plus a ground prong), then in addition to your US to UK adapter, you're also going to need a three to two prong adapter. You can find one in any hardware store for less than $2.00.
Although you can find voltage converters in Scotland, if you do need one, you'd be better off buying it here. As far as car chargers, most hired cars have a power point (like a cigarette lighter) for plugging in cell phone chargers, CD players, and the like. They are 12 volts, just like the ones here in the US, so your car charger will work in Scotland as well.
Hope that's helping.
Mike (Auchterless)