Continuity mistake: Before the school bell rings, Jason asks Ms. Darbus for her favorite summer memory. When everyone turns to look at him in the shot from the front of the class, there is a book under Troy's desk, which is not there in the previous or following shots. (00:01:25)
Continuity mistake: Just as they start to sing "What Time Is It" the top of Troy's boxers are visible above his belt. He starts out wearing light colored boxers, which change to dark, then light, and again to dark colored boxers during this song. (00:02:05)
Continuity mistake: Both Jason and Chad, who are wearing blue shirts and white aprons, are serving burgers, when Troy tells Chad that he wants Swiss cheese on his burger. Next shot in the kitchen, when Chad hands that burger to Zeke to add the Swiss, behind him Jason has been on kitchen dish duty wearing the green tee and blue apron. He can't be in two places at once. (00:57:55)
Continuity mistake: During "Work This Out" in the close-up when Troy sings, "A way to have fun," his name tag disappears, then reappears.
Continuity mistake: At the start, when the camera pans through the doorway, as Ms. Darbus speaks on the 'stage', there is nothing between Zeke and the doorway. In the next shot, a tall wood stool appears out of nowhere right beside Zeke. Also, the height and structure of the stool he is sitting on changes.
Continuity mistake: At the end of "Work This Out" the group take to the center of the kitchen floor for the final dance routine. To the left, the long white apron string either hangs down or lies on the table over and over again. (00:23:55)
Continuity mistake: At the start, when the camera pans through the doorway of Ms. Darbus's classroom, Zeke sits on a tall stool that is about 3 feet high. Oddly enough, in the following shots, the munchkin stool he now sits on only reaches the height of about 1 foot. (Did they really think we wouldn't notice?) The wood stool also moves forward a few feet. (00:00:50)
Continuity mistake: At the U of A basketball court, in the overhead shot Troy sits down beside a crumpled white towel, which disappears in his close-up as he calls Gabriella's cell. That towel returns in the subsequent overhead shot, when he continues to play basketball. (01:08:40)
Continuity mistake: The binoculars in Ryan's right hand disappears and reappears after the sprinklers have been turned on, when he and Sharpay spy on Gabriella and Troy. (00:27:15)
Continuity mistake: After Fulton gives the group their staff assignments in the kitchen, during "Work This Out" there are table order tickets hanging over the grill and fry stations. In some consecutive shots the amount goes from three to one, to three, to one, back to three, etc. (00:22:50)
Continuity mistake: As Gabriella and Troy dance out of Ms. Darbus's classroom, there are two books (yearbook and schoolbook) on Taylor's desk (in front of Jason). Next shot, when Ms. Darbus slams schoolbooks onto Jason's desk, there is only one book on Taylor's desk. (00:02:40)
Continuity mistake: After winning the Star Dazzle award, Ryan hugs Sharpay with the trophy in his hand. Part of the star at the top breaks off (watch Kelsi's face as it flies past her), as the rest of the star on the trophy bends down. In the next shot the star is intact. (01:43:05)
Continuity mistake: During "Work This Out" after Troy and Gabriella put away their spoons in buckets, the next shot Troy has a set in his right hand which he places on the table. (00:23:30)
Continuity mistake: During "All For One" at the pool party, mid-song the six singers split up into two groups of three - two girls and a boy and two boys and a girl; Sharpay, Troy and Chad walking down to their right (viewer's left) and Ryan, Gabriella and Taylor walking down to their left (viewer's right). Next shot, still singing and walking down, the three girls are walking to their left and the three boys are walking to their right. (01:46:20)
Continuity mistake: Before "Gotta Go My Own Way" in the kitchen scene, the bracelet on Gabriella's wrist is on her right wrist, but when she goes out to confront Sharpay, her bracelet is now on her left wrist. It stays on her left wrist until she gets to the lockers, then her bracelet is back on the right wrist and stays that way throughout the rest of the song. (01:13:50 - 01:19:55)
Continuity mistake: In the Lava Springs kitchen, Kelsi holds up a dish towel, when they sing, "Maybe there's a better way to fix this greasy mess," and she drops the towel. The towel repeatedly moves around from the cart's bottom shelf, to the floor and disappears repeatedly throughout the scene. (00:22:25)
Continuity mistake: When Miss Darbus speaks before the bell rings, there are two lamps, a cushioned chair and a small table, with a skull and teacup atop it, beside her. When the bell rings they all disappear from the platform. But note that when Chad dances with Ms. Darbus, one of the 'vanished' lamp's reflection is visible on the giant clock. (00:01:20)
Continuity mistake: When Troy jumps into the pool, there is a huge colorful beach ball right beside Troy in the water, but in the next wideshot when Gabriella jumps in, the ball has vanished - and most of the pool is seen in this shot.
Continuity mistake: Before Vanessa Hudgens' stunt double is seen diving into the pool, you can see Vanessa already in the pool swimming towards Ashley Tisdale as she stumbles backwards into the water.
Continuity mistake: The shadows of the players during the baseball game change from shot to shot; sometimes they are behind the players and others they are in front of the players. Even though shadows change positions during the course of the day, this is too rapid and out of sequence for a normal afternoon.
Answer: It's a Musical. Instruments that aren't shown are always playing like this in these types of movies.