“Behind the Curve” is a documentary showing behind the scenes on what is happening in the flat-Earth community in the United States just before a flat-Earth conference. In a section, the film shows us how a flat-Earther did an experiment involving a ring laser gyroscope, which proved the very thing he tried to disprove: Earth’s rotation; and that he was unwilling to accept the result.
He was able to formulate a decent hypothesis: If the Earth is spinning at one rotation every 24 hours, that means every hour it has to turn 15°. If a gyroscope is mounted on Earth, it’s going to drift with the same amount. A ring laser gyroscope is very precise and should be able to detect Earth’s rotation if there’s such a thing.
There’s an error in his hypothesis: if the gyroscope cannot detect the rotation, then the experiment fails to prove rotation, not that it disproves Earth’s rotation. Such results could have been taken as evidence for a stationary Earth, but cannot be regarded as 100% conclusive proof. However, if the gyro was able to detect 15° rotation, then it proves Earth’s rotation beyond any reasonable doubt.
And the gyro indeed showed the drift, so his errors were inconsequential. But instead of going with his initial hypothesis and conclude Earth is rotating, he was not willing to accept that and tried to disprove the result. He invented various ad-hoc hypotheses and even tested them. However, the gyro still indicates Earth is rotating.
On another occasion, to the producer of the film, he mentioned that he already spent $20000 on the “freaking gyro”, failed to disprove Earth’s rotation, but did not want to end up with what he regards as “failure.” He asked the producer to keep the conversation secret, which obviously was not heeded by the producer.
The film shows us that flat Earthers are not interested in the truth. They are only interested in confirming their beliefs. When faced with conflicting information, they would invent “explanations” on how that might happen. And when tests fail to confirm the “explanations”, they still will not let go of their irrational belief.