The function of a flask is to hold and store liquids. If graduated, it can serve to make approximate measurements of volume. One of the main advantages of a flask is the fact that the mixing of its contents can be done with little or no spillage. The flask is made of specialized glass so it can be heated and cooled without breaking. This same type of glass makes the flask brittle and it must be handled carefully. A stopper or cover allows for storage of liquids.
Update: June 2012