Phixius

Corrected entry: When Lorraine follows Marty back to Doc's in 1955 and Doc goes to answer the door, he says to Marty (before opening it) that it's his mum. Lorraine must have heard them through the door yet she never questions it.

Heather Benton

Correction: Two possible reasons she never asks about it. First, she simply did not hear him. You're assuming she did, but there's no evidence of it. Second, asking questions would be tantamount to admitting to eavesdropping. It's rude to eavesdrop and so Lorraine would hardly give herself away by asking questions about something she wasn't supposed to have heard in the first place, and which would have sounded nonsensical anyway.

Phixius

Correction: Besides, even if she did hear him, so what? She knew she obviously wasn't "Calvin's" mum. She would have assumed his mum looked like her and Doc mistakenly thought that was who was at the door. But if she still decided to question it, I just gave an explanation that they would have used.

Corrected entry: This one is tricky but important in view of Doc's concern about doing anything that will alter the future. The lightning rod on the clock tower would have been connected to ground with a thick cable. Doc would have had to disconnect this cable to allow the current from the lightning to flow into his cable instead and hence to the time machine. We now know that a lightning strike is a result of a complex interaction of electric potentials between charges in a cloud and charges in the ground below. By disconnecting this grounding cable this interaction would have been disrupted, causing the lightning to strike at a different time or strike a different object on the ground.

Correction: If you touch a lightning rod while lightning strikes it, you will still get electrocuted. So, just like the energy would travel into your body, it traveled through Doc's cable. No need to disconnect the ground. If grounding a power source kept it from charging any thing else, no electrical appliance would ever function.

Phixius

Corrected entry: When Marty travels back to 1955 the DeLorean first strikes a scarecrow, then drives at high speed into a barn and finally crashes through the barn door to escape. Later, when it returns to 1985, it crashes into a movie theatre front before it can stop. After all this mayhem the DeLorean doesn't have as much as a scratch on its nose.

Correction: That's because the entire body of every DMC DeLorean is made out of stainless steel, not fiberglass.

Phixius

Corrected entry: When Marty first enters Lou's cafe in 1955, Lou is visibly angry at Marty just because he won't order something right away. However, he doesn't seem to care that one of his paying customers, George McFly, is being harassed by Biff and his gang and told never to come in there again. You would think Lou would tell Biff and Co. to knock it off or else be asked to leave.

calidude

Correction: George had already paid for his cereal, what does Lou care? Biff and Co. are paying customers on occasion too, he wouldn't want to alienate them either. Especially considering they're likely to vandalize his restaraunt in retaliation.

Phixius

Corrected entry: Lorraine thinks Marty's name is Calvin Klein because she said it was written on his underwear. Actually, it's stitched on, which should tip her off that the underwear was made that way when it was manufactured, not written on.

calidude

Correction: Ever heard of embroidery? It's the process of using a needle and thread to put images or letters on cloth by hand. Lorraine undoubtedly assumed "Calvin's" mother had embroidered his underwear.

Phixius

Corrected entry: After Marty returns to 1985, he discovers that he now has the new Toyota truck he wanted, while the rest of his family is forced to share one car. Why would Marty, the youngest of the siblings, who is still in high school, have his own brand new truck while his older siblings and both parents have to share one other vehicle?

calidude

Correction: We only see one vehicle other than the truck, this does not mean it is the only other vehicle. We only know that Marty's older brother uses the car to go to work.

Phixius

Corrected entry: When Marty is hit by Lorraine's dad, it is right in front of the Baines house. If he was right in front of his house, then why was he driving so fast? He should have been slowing down to pull into the driveway or park, but he appears to still be going at a pretty good speed.

calidude

Correction: There's any number of reasons. Maybe he's just a reckless driver, maybe he was headed to the store after work to pick something up and his house happened to be between the store and his job. Just because you don't know why something happened does not make it a mistake.

Phixius

Corrected entry: When Doc is having the DeLorean do the burn out to get the car up to speed, the car is spinning its wheels up to 65 mph and Doc releases the brake. Now the car takes off, but the car would lose most of the speed the tires had built up as it is starting from essentially a dead stop even though the speedometer still shows 65 mph. Think of it this way, the back tires may be moving at 65 mph but the front tires are not. There is no physically possible way for a car to jump from 0 to 65 mph instantaneously using only its tires no matter how fast they were rotating. Even an F/A-18 needs a catapult to get that kind of speed so quickly. (00:21:35)

StopNGo & Girls

Correction: If the speedometer was hooked up in such a way as to show 65MPH as the speed before the brake was released, it would still show it afterward. The car was never going 65, true, but the tires were telling the speedometer it was. For whatever reason this is how Doc wired it all together. The tires wouldn't slow down suddenly just because the brake was let up, they'd continue to skid until the car's speed matched their own.

Phixius

Corrected entry: When Marty is plugging his guitar in to the mega amp, the amplifier end of the cable is stereo (like you would use for headphones) and the guitar end is the correct mono connector.

Lunchbox

Correction: This is obviously something Doc Brown built himself, not an "off-the-shelf" item. For whatever reason he wanted, needed, or settled on a stereo connection in the amp.

Phixius

Corrected entry: When Doc is on the clock tower attempting to reconnect the cable, he pulls it and disconnects the other end (indicating the cable has just enough slack to touch the ground from point A and then be inches short of point B). Doc then connects the cable and then ties the cable around the clock hands. The other end of the cable is only held by a fallen branch, if he were to really propel down the cable, he would have gone completely vertical down. When he lands, the cable would have been shorter due to him tying it to the clock hands. Also a shock of 1.21 gigawatts would have landed him in the hospital if not the funeral home.

Correction: Several "mistakes" in one entry, that alone should have gotten this entry rejected. The cable is more than long enough in a more or less straight shot from one end to the other. The branch is keeping from being a straight shot. That's why, even though it's wrapped arond the clock hand, it's still long enough after Doc disentangles it form the branch. If all of Doc's weight, and whatever more leverage he gained by pulling against the clock hand, wasn't enough to move the branch, him rapelling down the cable wouldn't have moved it either. It was stuck in place. The jolt he got wasn't a full 1.21 gigawatts either. The cable was surely insulated and he was wearing gloves, also certainly insulated, if I remember that small bit correctly.

Phixius

Corrected entry: At the very end, Marty tells Doc that he'll have to back up as they don't have enough roads to get up to 88mph. The next shot we see shows the avenue stretching off at least a mile into the distance, with plenty of road to reach that speed. Since the DeLorean was able to achieve 88mph in a parking lot, it should be fairly obvious to Marty that there is no issue with them not having enough road.

Correction: He's talking about road without intersections. It'd be less than desirable to ram into the side of someone's car at 87 miles per hour.

Phixius

Corrected entry: When Doc is on the clock tower in 1955 during the storm, a closeup of his feet is shown. He is wearing shoes with velcro straps in this shot. Velcro did not yet exist in 1955, and Doc had not yet traveled into the future.

Correction: The concept behind Velcro was conceived in 1941, the idea was submitted for a patent in 1951, and the patent was granted in 1955. Not impossible that Dr. Emmett Brown, a member of a wealthy family and fellow inventor, could acquire some.

Phixius

In a deleted scene the Doc is shown going through his future self's belongings and finds the Velcro shoes in his luggage along with the hairdryer that Marty uses as "Darth Vader." Doc simply "stole" the shoes from himself.

Corrected entry: American police may be so lackadaisical that they don't attend the scene of a car racing noisily around a car park, followed by a loud crash of a van hitting a shed, but I find it hard to believe that they don't investigate continuous machine gun fire from the same area. There are occupied building all around the car park, and there is plenty of time for them to turn up.

Correction: They'd have to receive a call from someone to be made aware of the situation. If the neighbors thought it was just some teenagers screwing around with firecrackers, which is more likely (because how often to Libyan terrorists open fire right next door?), the police wouldn't exactly rush to the scene lights blazing and sirens blaring. There's very few minutes from when the Libyans start firing to when Marty goes back to 1955, and who knows how far away the nearest police cruiser is.

Phixius