Can you give me some examples of recreational physics? Can you give me some examples of recreational physics?
Thx
 A: There is nothing such as "recreational physics". The term "recreational mathematics" is a standard umbrella term for mathematical puzzles and mathematical games. The term "recreational physics" may only be used by individuals who want to say that they find physics - whether theory or experiments - amusing. But they realize that no one will exactly know what they mean because "recreational physics" is not a standard term in the dictionary.
For example, this blog

http://www.recreationalphysics.blogspot.com/

was named "Recreational physics" because its author thought that it is an amusing title that combines physics and attractiveness. But the title doesn't mean anything specific and you won't find anything special on the blog that you wouldn't find on other physics blogs.
For physics to be "recreational" in the same way as recreational mathematics, there would have to be some "game" about them - a large number of possibilities that may always train our brains. But when it is so, it is mathematics. Physics, pretty much by definition, is all about "fully solving" problems. So if one has an amusing physics experiment, it may be viewed as "amusing physics", but if one does it - or understands it - once, there is really no point in doing the same thing again.
That makes a difference. For example, people may solve Sudoku thousands of times because it's always a bit different and they have always some "new fun". But if someone finds out that water may be frozen to ice e.g. in this way

http://www.youtube.com/watch?v=wzHXiGdMvkU

it's not terribly recreational to repeat the same procedure one thousand times because it's always the same hard work. ;-) The part of "physics puzzles" that may get modified deserves to be classified as "maths".
