Well,i hope everyone remembers the movie.In the shreiking shack,when sirius was speaking about his dreadful life,snape arrives and shouts "expelliarmus" and sirius gets disarmed without getting blasted off.But after sometime when Snape points the wand at sirius and offers harry to jinx sirius(apparently),harry shouts "expelliarmus" and snape gets knocked off!!How can this be possible according to the books?I mean....a spell should have a same effect irrespctive of time is'nt it?On the contrary....in the novel,harry,ron and hermione disarm Snape at the same moment and as a result snape gets knocked off!!This is a noticable mistake from a HP book reader point of view!!Anyway,what did you guys think about this?

Well I think every HP fan, who has read PoA, was kinda huh about that...

I know I was and still am...

I dont think there is any explanation exept that this is afterall the film not the book and some things are changed - and some without a reason...Im sure there are many other examples of the fact that the filmmakers change things ...

I dont know why they did it - I dont see the point, because they could have just done it like its done in the book but well I dunno...

i think maybe the director was trying to show how angry harry was beacause sometimes spells come out more powerful when u put feeling into it,
as for the part being different from the book, alot of the movie was! lol but i enjoyed both , but good question navya

I interpret it this way: Adults are far more adept at magic and are much more skilled in controlling their spells. Harry may have put too much emotion into the spell, or not enough concentration but the way I see it the kids spells work differently because they're more amateurs and aren't as skilled and as used to using such powerful spells as the order members are.

I think Emma is right about this.The movie was all about harry being angry is'nt it?The director might have thought of this idea as it adds to harry's anger.

I think it was just a simplification for the film. Also, Harry was using Hermione's wand, and wizards do not get the same quality of spells, or possibly the same control of spells when using other people wands.

I do think it was just a simplification though, which is kinda bad, since surely it would have been just as easy to have all three of them point and shout.

i neva noticed that mistake before

I reckon they just wanted to show Harry's cunningness etc by sneaking the wand out of Hermione's pocket. All the kiddies we're like "YAY Go Harry!", so I guess it worked.

WOW new mistake!

yeah i think you're right. in the scene we see, that harry is rather emotional, so that could make the spell more powerful than normally. but later, after they come out of the shack and harry disarms wormtail, he doesn't get blown off his feet. fona said, that it may be because harry didn't use his own wand in the shack, and as ollivander says in the first book: with the wand from someone else your work will always be different.

hmmn i think that sometimes emotion and hatred can contibute to how powerful spells come out. Like when Harry is learning to make his patronus he starts off just making a silverly sheen because he doesent have the ability or power to create a full one yet. However in the end he creates a giant one with power because he needs to. Understand what i mean? Pure speculation of course but it seems to be like that.

I've noticed quite a few mistakes in PoA... lol but yeah, that's always something I thought about myself because didn't that happen in CoS as well? The whole confusion with "Expelliarmus"?

Well- I noticed a lot of mistakes as well- but that's normal. You can't expect to fit the whole book sequentially into one movie- it just can't be done. I just think that they could have put it into the right order and left out some of the less important scenes.

The way I see it, it's not a mistake at all but actually true to the books. Emotions are meant to affect spells - Moody once told Harry in class that just saying the killing spell isn't enough, you have to FEEL it too. It's the same for everything else. Too much emotion would result in an over powered spell hence Snape getting bashed into the wall.

And sometimes the spells don't work right simply because they're kids, they're fallible and they're not yet fully trained wizards!

Exactly!^

one mistake that really annoyed me about POA was that harry got the firebolt after freeing sirius. Ahh!! it just ****** me off to no end. the viewer didnt get any of the tension that the reader about harry having his top of the line racing broom taken away because people thought it was from sirius black and that it was jinxed.

This is kind of stupid what I'm going to say, but Harry is much more talented than Snape. Harry has his own power and voldie's in him, so I always thought that's what they were trying to get across, that Harry is getting more powerful as he grows. Stupid I know!

Well at least they added it in. I don't think that everyone could ever be happy with this film. Its just impossible!

I interpret it like this:
Spells have have different "intensities" of their effects. Just as in CoS Snape used expelliarmus to disarm and knock back Lockhart, probably because he doesn't like him. He only disarmed Sirius because he didn't want to harm him, but take credit.
Harry used the same spell but it was intensified by his anger, just as his patronus becomes stronger with a stronger memory. The fact is it still disarmed the opposer, but with different intensities it can have stronger or weaker effects.

i think different people have different effect on the spells they are using . look at lockhart . he could hardly even disarm Snape, but his Memory Charm is way powerful ( it was his misfortune to have used Ron's wand) but oh well.. guess harry is just really good with Disarming . he used it against Voldie too. In PoA, the strength of hermione's wand+ Harry's anger+ the spell= goodbye snape, good luck.

Well, they had to put that in. To show that Harry recieved a Firebolt form Sirius. So people won't go 'Huh?' in the 4th movie. Besides, they had to put it that way coz' they had to cut off Wood from pestering harry to get a new broom.I miss Oliver.

hmmmmmmmmm yes I seem to remember that from the book I suppose they alraedy hadc enough material and didn't want to make the film longer than it already was

Good point. Wands in the wrong hands can have different results.

At the beginning of the movie they show Harry muttering a spell(Lumos maxima)...but that is against the law isn´t it...?Or was it said here in this thread before...I just wondered...

yeah you are right moxi....harry is not supposed to use wand outside hogwarts being an underage wizard.