A MUST-WATCH -- just 3 minutes of your time.
Space Hair -- AND ANOTHER FASCINATING POINT: why do Hollywood movies, commercials, etc. always turn the lighting down? Is it because it would look too familiar (=just like NASA footage) if they turned the lights up? I honestly never noticed or thought about this before I watched this video. Now I can't un-see it!
Another interesting thing you'll note with their "micro-gravity" situations. Theoretically, you're supposed to have no sense of up or down, but whenever they turn sideways, you'll notice that they bend their necks upward. That's the natural instinct; people try to keep their heads up. You would NOT have that instinct in actual micro-gravity.
Look at 47-57. She's craning her neck to the side attempting to keep her head upright. That means she senses up-and-down via gravity. That is a scene done with harnesses. If there were no gravity, she would not have that instinct, and there would be no sensation of up and down whatsoever. Some scenes are conducted on one of those "Zero-G" planes (when at NASA, I knew some people who rode on those from tiem to time). But other scenes are done with harnesses in normal gravity.
Finally, I saw one Youtube video which speaks of the "vestibular system", which helps human beings keep their balance and their sense of up and down. In a zero G environment, the discombobulation of the vestibular system has serious effects, from diziness and nausea to the loss of visual acuity, etc. This guy detailed all the effects of an impaired vestibular system and demonstrated that people living in a zero-G or low-G environment would be impaired to the point of being unable to focus and concentrate and perform any tasks that required concentration and fine motor control.