The first difference is that there were some scenes added or adapted in the movie, as opposed to the play. First, the large group of "stricken" girls, which indeed had a greater number than did the group in the play, left the church meeting at the beginning of the movie to see about Betty's condition. Betty seemed to be much more violent in the movie and she tried to jump out of the window, which did not occur in the play. These details were most likely added to augment the idea of "mass hysteria." A scene was added in the movie, showing the hangings and cheers of the crowd watching, also to add to that effect.
Another difference is that in the play, we never actually experience Tituba and the girls dancing in the forest, we merely hear about it later, and in the movie it is the opening scene. The scene was likely added for dramatic effect, and foreshadowing. oLastly there is a downpour of rain in several of the scenes directly before the trials began.
Thirdly there are many scenes included in the movie that are outdoors, however; there were no such scenes in the play. All of the action in the play was indoors. It is difficult to replicate an outdoors scene in a theatre. Also, some of the techniques used when filming outdoors create a symbolic message. A portion of the scenes before the beginning of the witchcraft trials is seen in a downpour of rain, possibly foreshadowing doom and dreariness to come.
In conclusion Arthur Miller's play, The Crucible, and the movie with the same name have many differences, all of which contribute to the individual effectiveness of each in conveying their central message. These include some