# Electrons Essay

2518 WordsFeb 25, 201211 Pages
Prior to doing this section you should have done a lab called Zap! Read From the Lab... for a summary of observations you should have made in that lab. One key observation from that lab was the Law of Charges. This is illustrated in the following movies and animations. In each, the clear strip of plastic gives the pith balls a positive charge. The white plastic strip gives the pith balls a negative charge. We'll learn how later. (Pith balls very light spheres made of soft wood.) Here we see a positively charged plastic strip giving a positive charge to each of two pith balls. As a result they repel. Here we see a negatively charged plastic strip giving a negative charge to each of two pith balls. They also repel. From these first two movies we see that objects with like charge repel. This time we have given the pith balls opposite charges. In this case they attract. This illustrates the second part of the law of charges, that objects with opposite charge attract.. You might also note that we see evidence that charge is being transferred from one ball to the other after contact. Just what is this evidence? We summarize this behavior in a rule often referred to as the Law of Charges. It's a bit of an archaic term, but let's use it since it's handy to have a name for this behavior. The Law of Charges Likes repel and unlikes attract. Here's one more look at this behavior. 1. Two charged bodies are some distance apart and experience a repulsive force. If the charge on one body is positive, the charge on the other must be positive negative 2. From our experience in the lab we also know that attraction can occur if one body is charged and the other uncharged. We'll return to that puzzle later. Just keep it in mind. So far... 2. The Bohr Atom So what is the source of all these electrical effects? Actually we don't exactly