I probably had more in mind for this article, but as it sat around for a very long time, I'm kicking it out the door.
People have a habit of agreeing a point with "sounds right".
That's an extremely credulous attitude.
There are plenty of things which "sound right" and aren't.
Flat Earth ∞
From the Wikipedia
Geodesy, also called geodetics, is the scientific discipline that deals with the measurement and representation of the Earth, its gravitational field and geodynamic phenomena (polar motion, Earth tides, and crustal motion) in three-dimensional time-varying space.
When at sea it is possible to see high mountains or elevated lights in the distance before lower lying ground and the masts of boats before the hull. It is also possible to see further by climbing higher in the ship, or, when on land, on high cliffs.
Anyone who has watched a boat sail away will see it drop down before it shrinks away in the distance. With a flat Earth, the boat would just shrink as it sails away.
Explaining climbing higher to see further is a little more difficult but follows the same idea. Assuming no other obstruction, distant objects are blocked by the roundness of the earth. Imagine a tiny person standing on the "north pole" of a beach ball. They cannot see south pole. They can't even see to the equator. Lift that tiny person up and they can see to the equator but still not to the south pole.
The sun is lower in the sky as you travel north, but stars such as Polaris, the north star, are higher in the sky. Other bright stars such as Canopus, visible in Egypt, disappear from the sky.
The length of daylight varies more between summer and winter the farther you are from the equator.
The earth throws a circular shadow on the moon during a lunar eclipse.
The times reported for lunar eclipses (which are seen simultaneously) are many hours later in the east (e.g. India) than in the west (e.g. Europe). Local times are confirmed later by travel using chronometers and telegraphic communication.
When you travel far south, to Ethiopia or India, the sun throws a shadow south at certain times of the year. Even farther (e.g. Argentina) and the shadow is always in the south.
It is possible to circumnavigate the world; that is, to travel around the world and return to where you started.
That is, you can travel in a straight line and not fall off the fucking planet.
Travellers who circumnavigate the earth observe the gain or loss of a day relative to those who did not. See also International Date Line.
The earth appears as a disc on photographs taken from space, regardless of the vantage point.
If it were flat, viewing it from space would make it deform out.
Several of these arguments have alternative explanations by themselves. e.g. the shadow thrown by a lunar eclipse ''could'' be caused by a disk-shaped earth. Similarly the north-south movement of stars in the sky with travel ''could'' mean they are much closer to earth. However, the arguments strengthen each together.
Multiple explanations all point to the same thing. Any single point which is undermined with a "possible" alternative explanation must be combined with other points to undermine every other point too.
Heavy things fall faster ∞
Some believe that heavy things fall faster, but they don't.
Why "sounds right" exists ∞
There are some problems which promote the sort of credulous attitude.
- People are frightened little children who want answers.
- People are lazy, and want answers handed to them.
People are lazy, and want answers to make sense without the need for education.
The problem is that a lot of legitimate answers are complex enough to require some decent thinking for them to be grasped fully. Understanding what a rainbow actually is takes some education and thought. "Zomg magic!" doesn't.
This is where god of the gaps arguments come flooding in. It gets worse when people intentionally refuse to look at evidence which flatly nullify their arguments. It's as though they stick their heads in the sand and pretend that if they don't consider facts their "side" has validity.