Electricity & Minerals

A Primer

Image credit: Scott Brande

The Bottom Line on Electricity - Here on Top!

Electricity is the energy of moving electrons. Electrons remain trapped in storage - a battery - until they can be driven into waves of motion by a voltage difference through a closed circuit. An electric current (waves of moving electrons) will pass through common metallic minerals like they do through a manufactured metal wire. 

Bottom Line: Metals are the highways for the flow of electrical energy in circuits. Mineral samples can be placed into a cheap flashlight to determine whether or not the mineral is metallic.

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What is a Metal?

"A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a material (an element, compound, or alloy) that is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally malleable - that is, they can be hammered or pressed permanently out of shape without breaking or cracking - as well as fusible (able to be fused or melted) and ductile (able to be drawn out into a thin wire). About 91 of the 118 elements in the periodic table are metals (some elements appear in both metallic and non-metallic forms).

Atoms of metals readily lose their outer shell electrons, resulting in a free flowing cloud of electrons within their otherwise solid arrangement. This provides the ability of metallic substances to easily transmit heat and electricity. While this flow of electrons occurs, the solid characteristic of the metal is produced by electrostatic interactions between each atom and the electron cloud. This type of bond is called a metallic bond."

Chemistry LibreTexts (2019). 6.C3:Solid Metallic Elements. Available at: https://chem.libretexts.org/Bookshelves/Inorganic_Chemistry/Map%3A_Inorganic_Chemistry_(Housecroft)/06%3A_Structures_and_energetics_of_metallic_and_ionic_solids/6.03%3A_The_Packing_of_Spheres_Model_Applied_to_the_Structures_of_Elements/6.3C%3A_Solid_Metallic_Elements  [Accessed 4 July 2019]

Elements on the Periodic Table

On the periodic table, most elements are classified as metals. https://www.britannica.com/science/metal-chemistry 

Drag image to scroll horizontally or vertically. (A more detailed periodic table online is here: http://www.syngentaperiodictable.co.uk/periodic-table.php?keyStage=5  )

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Earth's Crust- 'Big Eight' Elements

The composition of the earth’s crust has been studied for as long as rocks and minerals have been collected and analyzed. Here is an estimate of the ‘Big Eight’ group of elements that make up about 98.6% of the earth’s crust[i]

[i] https://www.science.co.il/elements/?s=Earth 

Metals and Civilization

Mankind has exploited the mineral resources of the planet for thousands of years. Metals that have played critical roles in the development of civilization lend their names to such archaeological “ages". 

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Metals, Minerals and Civilizations

Metallic Elements in Minerals

Some metallic elements in the earth are concentrated in nearly pure form, and some are in compounds with other elements. Here are some examples. 

Native (single element) minerals

Metallic Compound Minerals

Electrons and Electricity

Electrons in Metals

Image Attribution: Julen Aduriz EHU, Elektroi itsasoa, image annotations added by Scott Brande, CC BY-SA 4.0 

Electrons in Metallic Elements

The most important fact about metallic elements is that in a metallic crystal, specific outer electrons (like the outermost planets of our solar system) are free to move about the entire crystal because these electrons are not “attached” (bound) to the nucleus of their “parent” atom

Electricity - Electrons and Energy On The Move

Analogy - A Current of Electricity and A Wave in the Ocean

An analogy is a comparison of two things that are not identical. Usually one thing is familiar, and one thing is unfamiliar. So we come to better understand the unfamiliar thing by transferring our understanding from the familiar thing. Here is an analogy between waves in the ocean and electrical energy flowing through a metal wire.



Flashlight Electrical Circuit

What Is A Battery?

Image credit: Scott Brande

What Is An Electrical Circuit?

An electrical circuit is like a racetrack - a path along which electrons can flow. Here is a simple circuit in a battery-powered flashlight. If the circuit is open, a gap prevents electrons from flowing continuously around the circuit. A closed circuit permits electron flow which can power the lightbulb in a flashlight.

Image credit: Scott Brande

Image credit: Scott Brande

Parts of a Flashlight Electrical Circuit

What are components of a battery-operated flashlight?   Batteries are made with metallic elements, and small batteries power pocket flashlights. A simple flashlight can be modeled with only four relevant components.

Image credit: Scott Brande

Minerals As A Circuit Switch

Here are two examples.

Image credit: Scott Brande

Image credit: Scott Brande