Refraction is the change in the direction of light due to the change in the medium’s refractive index traveled by the light. It is convenient to use water in a demonstration of refraction. But water alone is not the cause of refraction.
Flat-Earthers falsely claim that just because our atmosphere has water vapor in it, it will produce the same effect as any demonstration of refraction involving water. In reality, it requires far more reasoning than just that water is involved.
Continue reading “Refraction and Water”
Flat-Earthers performed the coin on a table “experiment” to “explain” how a sunset can occur on a flat Earth. Instead, it tells us more about their confirmation bias.
This is probably one of the most ridiculous flat-Earth arguments. It is so obviously wrong that many of us are having trouble explaining it and cannot accept that a member of the human race can fall for it.
Continue reading “Coin on a Table “Experiment””
The entrance pupil is the opening in front of a camera that allows light to enter. If it is partially obscured, light can still come through the unobscured part, and the camera can still see the object.
In one of those “experiments,” flat-Earthers placed an obstacle in front of a camera, very close to the lens, so that an object is partially visible. At the widest angle setting, the person appears partially visible. But it turned out that zooming in will fully reveal the person. Flat-Earthers claim it is how objects can vanish behind the horizon if Earth is flat and how they can reappear by zooming in. In reality, zooming enlarges the camera’s entrance pupil, letting the camera to see over the obstacle.
Continue reading “Camera Entrance Pupil Size and the Zoom Factor”
Teaching aids are used by teachers to help students learn a subject more easily. A scale model of an eclipse is a teaching aid. It is not presented as evidence about how an eclipse can occur, but to help students to understand the mechanism of an eclipse.
Flat-Earthers often incorrectly consider a teaching aid is presented as if it is evidence of a phenomenon, then demand a similar thing as “evidence” of another phenomenon. In reality, a natural phenomenon is studied from the observation of the phenomenon itself. A teaching aid is there merely to help students learn.
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We cannot feel the Earth rotating, and to explain the phenomenon, we usually use the moving vehicle analogy. If the vehicle is moving at a constant speed, we will not be able to sense the motion. We cannot feel the motion of Earth because of the same reason.
Flat-Earthers invented the excuse that we are standing on Earth, not inside it, to falsely reject the explanation.
Continue reading “Moving Vehicle Analogy and the Physical Barrier Excuse”
Flat-Earthers like to use scale models to represent an actual object. They would apply the facts they observe from the model to the actual object itself. It is the fallacy of false analogy. The two situations can be substantially different. Just because both the scale model and the real object looks the same, it does not mean they are similar in another aspect.
Observation of the real object is stronger evidence than any argument from analogy —like using a scaled-down model of the real object. Using an analogy to dismiss the result of direct observation of the real object is unreasonable.
Continue reading “False Analogy in the Use of Scale Models in Flat-Earth “Experiments””
Gravity is the attraction between objects with mass. The higher the mass, the greater is the gravitational attraction. Gravity is not the result of the shapes of the objects.
Flat-Earthers like to perform the ball-and-water ‘experiment.’ They spray water to a ball, then observe the water does not stick to the ball the same way the ocean water curves over the surface of the Earth. They would wrongly conclude that “gravity does not exist.” Gravity does not come from the spherical shape of objects, Continue reading “The Ball and Water ‘Experiment’”
A false analogy is a fallacy in which similarity in one respect of two concepts, objects, or events is taken as sufficient to establish that they are similar in another respect in which they are actually are not similar.
Almost all of what flat-Earthers happily claim as “experiments” are actually false analogies. They would take everyday objects and use them as analogies for actual objects. In reality, a shared similarity in both the analogy and the real thing is not sufficient to ‘prove’ both are similar in some other respect.
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A properly designed football field does not lie perfectly flat. Its middle portion is slightly raised to promote runoff of excess water. Without it, the field can become muddy & uncomfortable.
Some flat-Earthers conducted the perspective convergence ‘experiment’. They put a camera on the surface of a football field, and record a person walking away across the field. The person started to disappear from his feet first. Because they felt the football field is flat, they took the wrong conclusion that the person disappeared due to ‘perspective’. They were wrong. The field is, in fact, not perfectly flat. If it is perfectly flat, the person would appear fully at the end of the field.
Continue reading “Football Field and ‘Flat-Earth Convergence Experiments’”
We often see flat-Earthers create a ‘miniaturized physical model’ of a real object and present them as ‘proof’ in support of flat-Earth and against spherical Earth. Their M.O. is to observe if the model remotely resembles the actual object in a particular way. If it does, then it is enough for them to conclude the model describe how the real object works.
Conversely, if a real object cannot be miniaturized and still have the same behavior as the original object, they would conclude that the behavior of the original object doesn’t exist.
They would wrongly call creating such models “doing an experiment”.
Continue reading “The so-called “Experiment” Done by Flat-Earthers”
“If the Earth is rotating, why when we throw a rock upward, it would fall to the original location?” The explanation is that the rock maintains the momentum before it is thrown. Before it is thrown, the rock has the same velocity as the surface of the Earth, it does not suddenly lose its momentum after being thrown, and there’s nothing exerting a force to alter its trajectory.
We usually use the moving vehicle analogy to illustrate this. If we throw the rock upward inside a moving vehicle, it would also fall to the original location, despite the fact that the vehicle is moving.
Flat-Earthers reject the analogy. Their usual excuse is that the atmosphere is not separated from space, and the rock is thrown “inside” the vehicle, separated by the body of the vehicle from the outside. They offer the analogy of being on the top of a moving vehicle as the correct analogy. They are wrong.
Continue reading “The Moving Vehicle Analogy”
Kettle logic is making multiple contradicting arguments in an attempt to support a single point or idea.
Kettle logic occurs very frequently in the flat-Earth community. If they meet a natural phenomenon cannot readily be explained using the flat-Earth model, they would often devise ‘experimental models’ to ‘explain’ how the said phenomenon can happen in a flat-Earth.
The problem? These models are in conflict with each other.
Continue reading “Kettle Logic: Conflicting ‘Explanations’ in the Flat-Earth Model”
The surface of the water in a glass of water is practically flat. Some flat-Earthers claim this is ‘evidence’ that the surface of the water is flat, and it will always be flat no matter how wide the container. They are wrong.
If the Earth is a sphere with the radius of 6371 km (3960 miles), then the surface of the water in a 10 cm (4 in) wide glass will have a bulge of 0.00000002 cm as the result of gravity, excluding other effects like the surface tension.
Continue reading “A Glass of Water”
Humans have cognitive biases that can affect our judgments. One of these cognitive biases is the confirmation bias. Because of the confirmation bias, we tend to seek the information confirming our preexisting beliefs.
Confirmation bias is a fact of life, and all humans have it. Confirmation bias can result in different subjective opinion from a different subject. A characteristic of any pseudoscience —like the concept of flat-Earth— is that they don’t try to minimize the confirmation bias, but they actually encourage it.
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The mass of the Earth exerts the gravitational acceleration of about 9.82 m/s² to everything on Earth’s surface toward the center of the Earth. On the other hand, the rotational motion of the Earth generates the centrifugal acceleration of about 0.03 m/s² away from the Earth. The net acceleration is about 9.79 m/s² toward the center of the Earth. That is why everything on Earth’s surface stays on the surface, not flying away to space.
Flat-Earthers often make a false comparison using a wet & spinning ball. Water on the surface of a wet & spinning ball does not stick to the ball, but the Earth is also round, wet, and spins, yet everything stays on the surface. Then they make the erroneous conclusion that the Earth cannot be a spinning ball.
Continue reading “The False Analogy of a Spinning Tennis Ball”