Corrected entry: At the beginning of the movie, when we first see Admiral Boom's house, we see that the Banks house right next store is also a 2 story home. However, the children's nursery is on the third floor (up 2 flights of stairs). There is no third floor.
Corrected entry: During the clean up of the nursery scene, a group of hats, including Jane's straw hat with the brown velvet ribbon, fly into a closet and hang on hooks. Above them is a shelf with boxes. When the clean up is complete and the children and Mary Poppins are getting ready to go out, Jane retrieves the same hat, now on the shelf instead of the hooks, and the boxes that were on the shelf are gone.
Corrected entry: Some of the rockets in which the captain's assistant puts into the cannon have duct/masking tape around them. Duct/masking tape wasn't invented then.
Corrected entry: In the scene after they have finished cleaning the children's room and are leaving to go to the park, half of one of the beds is missing.
Corrected entry: Near the end, just before "Let's Go Fly A Kite", when Mr Banks has returned home his detachable collar is detached on his left-hand side in shots from the front but not from the back of him.
Corrected entry: When the cook attacks the chimney sweeps, she uses a non-stick frying pan. Non-stick frying pans weren't invented until the 1950s, and the movie takes place in the 1910s.