## Earth Gravity – Distinguishing the Forest and Trees

There's no point attempting to explain the precise nature of gravity here. Most of us are aware it is Earth gravity that enables us to remain standing on the planet. Gravitational force operates on all matter.¹ Is Matter the Same as Weight? No, the two are not the same. To illustrate, say a man is seated at the doctor's office and he is invited back. He is requested to stand on a scale. It says he weighs 210 lbs. We write w = 210 lbs. Now say that man is an astronaut. Ah! Next week he is deep in space. If he removes his restraints, he begins to float. He is weightless!² That is, w = 0 lbs. Yet his mass remains the same. That is, m ≠ 0. Weight…

## Factors that Complicate Atomic Mass Determination

[caption id="attachment_8319" align="alignright" width="440"] Nucleus - CC-SA-3.0 by Marekich[/caption] Modern chemistry depends a good deal upon accurately knowing the atomic mass of each of the elements. What factors complicate determining those values? Each of the approximately 90 different natural-occurring elements possesses a nucleus or central core of protons and neutrons, in addition to electrons that orbit around the nucleus. It is important to the chemist or physicist to know the total mass of each element. Can correct values be obtained simply by summing the weight of individual particles in an atom? After all, each of these particles has a precisely known mass. The answer is, No! Such calculations disagree with experimental measurement. An example illustrates the point. Consider Helium-3 An atom of helium-3 has two protons, one neutron, and two…

## Calculate Atom Weight Two Ways

[caption id="attachment_8437" align="alignright" width="400"] Radon atom statistics.[/caption] Ever wonder how much an atom weighs? One atom. Different varieties of atoms weigh different amounts—helium weighs one thing, lead another. But how can the weight of any sort of atom be determined to within reasonable accuracy? We present two simple methods to calculate atom weight. Two Ways One can calculate atom weight from knowing the weights of the constituent electrons, protons, and neutrons. If you know the weight of each of those and the number of each in an atom, you can readily calculate its weight. Yet, there is an easier and a better way. Let’s pick an element out of the hat. Let’s take gold (If we can’t afford it, at least we can talk about it.). To calculate atom weight…