To summarize, protons and neutrons are in the nucleus of an atom, and tightly bound together. The proton has a positive charge while the neutron has no charge, and both of them are much larger than the electron. The tiny electron is outside the nucleus and weakly bound to the atom and carries a negative a charge.

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Go get a balloon. The rubber latex kind work the best (not the shiny Mylar kind). You’ll need it for the next set of experiments we’re going to talk about below. When you rub a balloon on your head, you charge up the balloon with a negative static charge. But how much charge is it? The units of charge are called the Coulomb (C), just like the units of time are seconds (s). And just like seconds, you can have microseconds (10^-6 seconds) and nanoseconds (10^-9 seconds), you can have microCoulombs (10^-6 C or μC) and nanoCoulombs (10^-9 C or nC).

The charge of one electron is -1.6 x 10^-19 C… it’s a really small number! The charge of one proton is +1.6 x 10^-19 C. The kind of charge (whether positive or negative) is determined by how many extra protons or electrons are present in addition to the ones that are evenly matched to balance the charge. If an object has 15 protons and 17 electrons, then it’s got a negative charge by 2 electrons. Just because an object is not charged (electrically neutral) doesn’t mean it doesn’t have any protons or electrons. Rather it means that the number of electrons and protons are evenly matched to balance the charge of the object. We say that charge is quantized, which means that electric charge isn’t a continuous fluid flow, but instead is made up of tiny packets of charged particles. The charge on one electron is -1.60 x 10^-19 C.  This is one of the most fundamental concepts in physics! 

Click here to go to next lesson on The Charge of Lightning.

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