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.

Errors/Suggestions: Contact Scott Brande (see footer) or post on Discussion Forum.

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 )

Click Pie Chart to Pop-Out Enlarged Image

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".

Click tabs below table to display data

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

  • Electricity is a property of matter that refers to the movement of electrons.
  • When electrons in bulk are moving about randomly, this motion is called "static" electricity.
  • When electrons move in coordination, the motion is called "dynamic" electricity.

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

  • An analogy called "Newton's Cradle" (click link to view). One ball collides with the next, transferring its kinetic energy (energy of motion) to the next ball. So the first ball stops and the energy it transfers sets the second stationary ball into motion. And so on.
  • An analogy of falling tiles. A video (below) shows the transfer of energy from one falling tile to the next in line. Each falling tile transfers energy to the next during its impact. The movement-collision-energy transfer moves the domino-like sequence through the chain.

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.

Ocean

  • The ocean is made of water molecules.
  • A wave of energy in the ocean passes through seawater.
  • An ocean wave of energy is passed from one water molecule to the next.
  • The energy wave moves faster than the water molecules.

Electrons

  • A metal wire is made of metallic elements.
  • A wave of electrical energy passes through a metal wire.
  • An electrical current of energy passes from one electron to the next.
  • The electricity current moves faster than the electrons that pass it along.

Click image to animate motion of ocean wave

Flashlight Electrical Circuit

What Is A Battery?

  • A battery is a package of stored electrons that can do work.
  • A battery is like your bank account. Just as you can deposit or withdraw money from your account, in a battery, the energy of electrons can be deposited (when the battery is recharged) and stored, or withdrawn (when the battery discharges electrons that light the bulb). Chemical compounds in the battery are the storage containers for electrons.
  • The wizards of chemistry have figured out how to use various chemical compounds as shuttles (carriers) of electrons from one end of the battery (the positive (+) terminal) to the other (the negative (-) terminal).

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.

  • Open circuit - a gap in the circuit is caused by the open switch. Electrons are unable to cross the gap.
  • Closed circuit - the gap is closed when the switch makes contact with the circuit. Electrons flow continuously around the completed circuit.

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.

  1. battery
  2. lightbulb
  3. connecting circuit (metallic wire)
  4. switch

Image credit: Scott Brande

Minerals As A Circuit Switch

  • Any solid may be placed into a circuit between two open ends of the wire.
  • If a non-metallic mineral connects two ends of the wire, no electrical current will pass through the non-metallic mineral and the bulb will not light.
  • If a metallic mineral connects two ends of the wire, an electrical current will pass through the metallic mineral and the bulb will light.

Here are two examples.

Image credit: Scott Brande

Image credit: Scott Brande