<p>Can someone tell me what Strong typing and weak typing means and which one is better?</p>

Weak typing means that you don't specify what type a variable is, and strong typing means you give a strict type to each variable.
Each has its advantages, with weak typing (or dynamic typing, as it is often called), being more flexible and requiring less code from the programmer. Strong typing, on the other hand, requires more work from the developer, but in return it can alert you of many mistakes when compiling your code, before you run it. Dynamic typing may delay the discovery of these simple problems until the code is executed.
Depending on the task at hand, weak typing may be better than strong typing, or vice versa, but it is mostly a matter of taste. Weak typing is commonly used in scripting languages, while strong typing is used in most compiled languages.