Elsewhere in the Trek canon, it's mentioned that full impulse power is 1/4 the speed of light. When they go to find the whales near the end of the film, Kirk orders full impulse, and Sulu says "12 minutes". 12 minutes at 1/4 light speed would put them about 33 million miles away from Earth. [It has also been established that impulse drive functions differently and is much slower in a planet's atmosphere due to turbulance.] Corrected by MovieGuy

In a scene with Norwegian whalehunters, the sailors speak Finnish not Norwegian. They are also using somewhat obscene words, maybe all sailors do. [There is a minority people in Northern Norway called the Kvens. They originally came from Finland, and the language they speak, the Kven language, is still quite close to Finnish even though it has adapted at least some lexical aspects from Norwegian. Being a Finn, I understand what the whalers say, but can recognize some words that are more Norwegian than Finnish.]

When Spock announces "Gracie is pregnant," Gillian slams on the brakes and stops her truck. Look at the convex mirror on the passenger side next to Kirk. Despite the fact that there are joggers and other things moving in the background, there is no movement in the mirror; at that angle the viewer should have seen lots of movement in the convex mirror. [In the brief moment the convex mirror is shown as the car stops, its reflecting side is not visible. The rest of the scene is an interior shot, the mirror is not visible, and there is plenty of action in the background.]

Starfleet has serious regulations on bringing future technology to inappropriate time periods (which is why the Bird of Prey remained cloaked during it's time in 1986). Chekov being fully aware and considerate of these regulations, considering he has been in Starfleet for about 20 years should have never tossed the Klingon phaser (23rd Century technology) at the navy officer (20th Century person) with full knowledge that he'll never be able to retrieve it. He is too smart for it to have been panic. [Maybe a bad error in judgment, but a character mistake, not a movie mistake.] Corrected by wizard_of_gore

At the Start of the Final scene of the film, when the crew are approaching the new Enterprise-A in the inspection pod, Kirk is correctly wearing a Captain's Rank Pin on his tunic, however, his tunic still has the gold braiding of an Admiral. [Kirk probabaly hasn't had enough time to fully update his uniform.]

As they descend into the park, Uhuru gives a bearing and range of 283 degrees, 15.2 kilometers to the whales, which are supposedly in a marine park in Sausalito. 283 degrees would put you in the Pacific Ocean, because Sausalito bears around 350 from the park. [Bearing is given depending on which direction you are facing, it is not a set measure. If you are facing North, then West is bearing 090, but if you are facing East, it is bearing 180.]

In the operating room, just after Kirk welds the lock shut, Bones is leaning over Checkov, he reaches out his hand and we assume Dr. Gillian hands him the piece of equipment that he puts on Chekov's forehead to heal him. How did she know what equipment to give him as it was from hundreds of years into the future and Bones doesn't actually ask for it? [Bones says to Dr. Gillian "We're going to have to look like physicians." He could have explained the device to her while she was telling him how to look like a 20th century physician.]

In a scene early in the movie where Spock is being tested by 3 computers the computer output is being displayed on clear screens that look like teleprompters. One of the camera angles is looking up at Spock from behind the screen. To the viewer the words in the question are backwards (forwards to Spock), but when the word "Correct" is displayed it is forward to the viewer (backwards to Spock). [There are 2 screens for each computer, one facing Spock, the other facing away from him. Everything that appears on Spock's screen appears exactly the same direction on the other screen, and both the questions and the word "correct" appear forwards.]

When Kirk, McCoy and Dr Taylor escape from the hospital with Chekov, they are "beamed out" of the elevator and "beam" back in at the park next to the Bounty. My understanding is that the transporters can "beam" people from the transporter itself to another place, or from another place back to the transporter, but not from another place to yet another place. I realise that this is required in the movie, because when they arrive back at the Bounty, Kirk tries to tell Dr Taylor she can't come with them, which would have been awkward if they were on board at the time, but it is still a small mistake. [Transporters are quite capable of doing what's depicted in the film - it's generally referred to as a site-to-site transport. It's not something that happens terribly often in the films and series, for the simple reason that it's not often required and it takes up a lot more power than a simple transport to or from the transporter pad itself. But they've always been capable of doing it.] Corrected by Tailkinker

In the scene where Gillian picks up Kirk and Spock as they are walking back from the Cetacean Institute, Gillian asks, "Where are you going?" to which Kirk replies, "Back to San Francisco." They are already back in San Francisco, walking along the Marina Green. In fact, if we assume they are walking back to their ship in Golden Gate Park, they're going the completely wrong way. [The expression "Back to San Francisco" from where Kirk and Spock are standing is completely appropriate. The Golden Gate Bridge is at the edge of the city, and the downtown area and attractions are several miles to the east, along the northeast edge of the peninsula. So, while they are legally within the city limits, they have quite a ways to go before getting to the main part of the city.]

Between ST3 and ST4, the bridge set of the Bird of Prey changes from a two-level room with the captain on a raised platform and the crew in front of him, to a one-level room with two stations behind the captain and a console in the front. [During the crew's exile on Vulcan, between ST3 and ST4, Scotty made a number of changes to the Bird of Prey. Presumably, these included changing the bridge configuration.]

In the scene where they are landing the cloaked Klingon ship in Golden Gate Park, it crushes a garbage can and depresses the ground several inches. However, after the ship lands you can still see grass blowing in the wind under where the ship is supposedly sitting. [The ship itself is not sitting on the ground - the landing gear are holding the ship up, much in the same way they would hold up an airplane. Thus while the legs are in contact with the ground, there's open air under the hull.]

Reactor rooms are sealed spaces. No marine with a dog would be able to patrol it, especially without a radiation suit. [The room is a *restricted* space, if it were sealed how would they use anything inside of it? And you would not need a radiation suit to enter a reactor room, the reactor itself is radiation shielded so that it doesn't leak.]

Didn't the crew notice on their sensors that there was a garbage truck with two garbage men in the park, right next to where they landed? [The crew are in a alien vessel that they learned to fly themselves so they don't know everything about it & they're also in a time that they're not familiar with. They may not have known what the garbage truck was & didn't see the men as they were too busy landing for what was probably only the second time.]

In the scene where the ship lands in the park, a garbage can is blown around, and then crushed by the ship. But a ship landing would cause things to be blown away from where it was landing, and the garbage can is blown from outside where the ship lands to directly under it, almost as if the landing ship was sucking the can under it, which would not happen. [Not necessarily. If this can were placed between two of the thrusters, it could very easily be blown to the place exactly between them which would have made it even more likely that it would be placed directly under one of the central landing gear struts.] Corrected by Garlonuss

The reactor compartment can be seen though a window and billowing steam or smoke is visible. While a neat effect, the steam produced in a reactor is contained in piping. Smoke or steam visible is a very "bad" thing - like 3 mile island or Chernobyl. [I can't find any smoke or steam. Which reactor are you referring to? If you are referring to the nuclear reactor on the Enterprise, then a timecode would be greatly appreciated. However, if you are referring to the reactor on the Bounty, that is a Matter/Antimatter reactor mediated by dilithium crystals and does not necessarily follow the same rules as a nuclear reactor.] Corrected by Garlonuss

Chekov and Uhura beam aboard the USS Enterprise (air craft carrier) to collect radiation to recrystallise the dilithium so they can leave. When I served aboard a nuclear powered ship, we normally shut down the reactor after we came into port. There is negligible amount of radiation produced from a shut down nuclear reactor. [True, but Star Trek technology is far in advance of ours, so they were able to get what they needed even from a shut-down reactor. It would be like using a lighter to start a caveman's cold fire after he gave up rubbing sticks together.] Corrected by Grumpy Scot

Why bother traveling back to 1986 to get a whale? Why not travel back to the year 500, with no hostile people around. After all; they claim that the whales have been around for 10000 years or so... It can't be the need for nuclear fuel, because Scotty discovers the problem with the Klingon dilithium crystals AFTER the crew has travelled back in time. Only after discovering the problem does the crew decide to collect high-energy photons from a nuclear reactor. At the time they were deciding to go back in time, they had no idea there was going to be a problem with the crystals. Hence, the logical decision at the time would have been to go back to the distant past where the risk to the time continuum would have been minimal. [Time travel is imprecise, especially the "sling-shot" technique they used (compared to other methods in other films). They could not aim for a specific year, and Kirk does ask what year it is. Probably they were just trying to get to a time when Hump-Back whales were still around and weren't thinking about what time period they were going to end up in. From the film makers stand point, it would have been easier to have them go to "present" time, rather than farther back.] [The crew needs not only a whale , but also the technology and materials to build the 'fishtank' inside the Bounty. Hence , they would travel to a time where such materials had already been invented.]

In the scene near the end of the movie where the crew is celebrating in the San Francisco Bay after the probe has left, Spock appears to be smiling and laughing as everyone frolicks in the water. Doesn't this go against his Vulcan suppression of emotions, which historically only came out when something was wrong with him? [Spock is half human, half vulcan. Maybe his human half reacts in that moment very strongly and he can't hold his emotions.]

When Kirk and Spock go to get money, Kirk sells the glasses that Bones gives him for his birthday. Spock questions him about this, and Kirk says that Bones will give them to him again. That would I suppose would be theoretically possible except they return to their time moments after they leave, not before they leave. [This is not a mistake. This is an example of a "temporal causal loop" phenomenon. Chain of events: Bones buys or receives glasses. Bones gives Kirk glasses. Kirk sells glasses to antiques dealer. Antiques dealer fixes lenses. Glasses go through a chain of people through the intervening years from the antiques dealer to Bones. Bones buys or receives glasses... You get the idea. While Kirk won't have the glasses back when they get home, he will still be given them for his birthday in the future.]