OK. So my first question to everyone is why do flat earth members not believe in atoms or molecules? Of all the potential scientific claims in existence, the clear observations of molecules and their composition show a predictable sub-molecular structure. These are known as atoms... Furthermore, from my short period of reading through the different threads and youtube videos, I understand that flat earthers do not like to accept the common scientific know-how. However, one of the most observed structures in material science (and is repeatable over and over) is "X-Ray Diffraction". Using this method of investigation you can take various types of crystals or thin-films (e.g. silicon, GaN, AlGaN, InGaN, etc...) and apply high energy particles such as x-ray which will produce a pattern (also known as interference patterns). These patterns provide the structure of the atoms which make up the crystal being observed. There is no other phenomenon for this and can be used to predict the exact type of crystal material.
Additionally, when using certain formats of x-ray diffraction such as high-resolution x-ray diffraction (HRXRD, XANES, XTEM, or even AFM) you can see the density of the electrons and orbitals in the atom. I USE THIS EXAMPLE because we do this type of testing on our semiconductor crystals all the time. We usually take a sample out of every batch of monocrystal wafers and analyze them for QAQC purposes. I will be happy to post images from these test, and hope that with this we can lay an agreed upon foundation that atoms and molecules exist and that is what all matter is composed of. This is important as I want to show more data from some of the long-range RF and EM propagation we have done over long distances (>30 miles) sea and land.
You can also look into this yourselves. It has been used for almost a century... x-ray diffraction "X-Ray Crystallography"