Glossary of Terms


Amber comes in several colors (mostly shades of yellow) and can look like a clear stone. It was actually made from the resin of trees that were extinct millions of years ago. The trees died, fell, were covered with dirt, dead leaves and other decaying material called sediment, and over time fossilized into what we call amber today.

In addition to being used by many cultures as jewelry, amber also captured many insects before it hardened. Scientists use it to identify many species that lived during that time. Thales of Miletus also found that if amber was rubbed with silk, objects not normally attracted to it could be. Any of the online encyclopedias can provide a wealth of information on this topic if a deeper understanding is desired.



Current is the flow of electric charge. By convention, we say that current flows in the direction of high potential (+) to low potential (-).


Electric Charge
For this website, we will restrict the definition of electric charge to a fundamental property of particles that make up an atom. A proton has a single unit of positive charge, an electron has a single unit of negative charge and a neutron has no charge at all.

While it is true that particles do exist with partial units of charge (quarks, for eg.), and while the above definition will not satisfy those who are looking for an in-depth study of the term, we’ll leave that for the advanced physics folks to ponder. If you would like to find more on the subject, try “Googling” Electric Charge, or better yet, start with and just try to keep up with all the directions that will take you. Happy hunting!



For this site, an electrolyte refers to the substance inside a battery that the battery’s terminals are submersed in. Technically this is an electrolytic solution, and is usually a paste or liquid with the ability to conduct an electric current. Acid in a car battery, fruit juices in the lemon, apple and potato battery experiments, and salt water in the coin battery project are all good examples.

For more info, try or


Lodestone (or Loadstone)

In the context of this site, the term lodestone refers to a natural magnet. Lodestone is a special form of magnetite that the Chinese used in ancient times as quite possibly the first known compass. As a natural magnet, lodestone will also attract magnetized iron.

For an in depth discussion of Lodestone, try:



It is difficult to do better than the Wikipedia definition for this one … “In physics, magnetism is one of the phenomena by which materials exert an attractive or repulsive force on other materials. Some well known materials that exhibit easily detectable magnetic properties are iron, some steels, and the mineral lodestone; however, all materials are influenced to greater or lesser degree by the presence of a magnetic field”.

For the full article, see



Magnetite is a form of iron oxide. It is the most magnetic mineral, and if it contains just the right crystalline structure, it is known as loadstone, which was used as one of the first known compasses.

If you need to learn more about Magnetite, a good place to start is:


Resistivity and Resistance

For this site, resistivity is a property of the material in a wire, “resistor”, insulator, or other component in an electric or electronic circuit. Resistance in any of these devises is directly related to this property. The resistance in a wire, for example, increases as the resistivity of the material used to make the wire increases. In this example, resistance also increases as the length of the wire increases or the thickness of the wire decreases. Since resistivity itself increases with temperature, so too will the overall value of resistance in the material.

Resistance is measured in units called “ohms”, and the higher the value of resistance, or the higher the number of ohms a device has, the more that material will oppose a flow of electric current through it. If we are designing a room heater or a hair dryer, this is what we want. Most of the time, however, this represents a loss in our circuit that must be dealt with, as it also affects the efficiency at which our device operates.

It is difficult to do much better than Wikipedia for additional information on this topic if needed.



Our use of the term “Series” relates to how components are connected in an electric circuit. If we start with a battery, for example, and connect a wire from the (+) terminal of that battery to a load, like a light, then connect the wire to another light and then back to the (-) terminal of the battery, the current flowing through both the lights and the battery will be the same but voltage will drop after each load. This is an example of connecting circuit components in series.

If at the end of the second light in the above example we were to connect the wire from the last light to the (-) terminal of a second battery, and the (+) terminal of that battery to the (-) terminal of the first battery, then it is still considered a series connection. We still have a voltage drop across the first light and a voltage drop across the second light, but we also have a voltage increase across each battery this time instead of just one. In other words, the overall voltage in the circuit will be the sum of the voltage drops and rises across each component in the circuit.


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