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Consider the following experiment

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You have two pieces of metal: copper and zinc

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which you connect to conducting wires

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and you then submerge the metals in an electrolyte

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in this case vinegar

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You will observe that bubbles will form

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around the zinc but not on the copper.

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The metal seemed dissimilar in this way

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and if you then connect the two wires

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holding the metals, something changes.

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Tiny bubbles begin to form around the

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copper terminal. It seems as though

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something is being pulled from the zinc

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through the wire allowing a reaction to

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occur on the copper side and it turns

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out this is a flow of electrical charge

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as electrons are pulled away from the

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zinc towards the copper through the

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conductive path in the wire.

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Think of this blow as the result of a

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charge imbalance or electrical pressure

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between the two metals as compared to

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the instantaneous discharge observed

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with static electricity experiments.

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Towards the end of the 18th century

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Alessandro Volta had been investigating

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this effect. More importantly he found

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that chaining these cells together

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would amplify this flow of charge.

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And by 1800

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he simplified things even further

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removing the jar which provided more

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electrolyte than was actually needed.

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He writes, "- A few dozen small round disks of

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copper, [pieces of coin for example], and

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equal number of plates of zinc.

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- I prepare circular pieces of spongy matter capable of retaining water

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- I continue coupling a plate of copper with one zinc and always

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in the same order and interpose between

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each of these couples a moistened disk.

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This continues until I have a column as

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high as possible without danger of it falling."

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This is known famously as the

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voltaic pile, the first battery in

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history to provide a continuous flow of

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electrical charge, or current. More cells

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resulted in an increased electrical

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pressure at the two ends and electrical

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pressure was an early term for what we

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now call voltage after Volta.

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Now if the two leads of a voltaic pile were brought

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into direct contact, a series of shocks

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could be observed.

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Now at first the utility of electric current as a

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communication method was not immediately

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obvious, aside from faint sparks and bubbles.

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One idea was to use the presence

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of bubbles to signal letters and the

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Bubble Telegraph used this method though

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it involved 26 different circuits, one

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for each letter and it was based on the

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fact that the battery providing the

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current can be placed at a distance away

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from the jars containing the leads

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creating the bubbles.

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An inventive although clumsy system

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which was never adopted.

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But very soon everything changed after a

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famous demonstration in 1819. It was

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found that if we simply pass a wire near

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a compass and connected to a battery as

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soon as the wire made contact with the

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battery the needle jumped without any

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physical contact. The only explanation

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was that the current carrying wire was

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creating a temporary magnetic field.

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This was followed by a series of tasks to

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figure out the direction of this field

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first we assumed it was pointing along

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the wire with the current or perhaps

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emanating outwards from the wire as heat

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would travel.

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But eventually it was deduced that it must be traveling around

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the wire in perpendicular circles, so a

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loop of wire would create a magnetic

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field which points through the center of

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the loop and around the outside.

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This lead to the galvanometer which was designed

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to detect and measure electrical current

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and it was just simply a coil of wire

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with a compass suspended in the center.

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Now when electric current was applied to the coil,

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a magnetic field would push through the

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middle of the coil and around the

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outside so the needle would always point

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perpendicular to the direction of the

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force which was balanced on either side

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of the needle, and the stronger the

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current the stronger the deflection of

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the needle.

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And by 1824 William Sturgeon

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demonstrated a way to increase the

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strength of this field even more, simply

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by wrapping a coil of wire around a

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piece of iron such as a nail the

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magnetic force could be amplified

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because iron seemed to be a better

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medium for supporting the formation of

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magnetic fields. We call this

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"permeability" and by wrapping the wire

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many times the strength of the field

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could be amplified thousands of times

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and this is known as an "electromagnet".

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So suddenly it was possible to create

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magnetic fields which could move needles

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with precision and force using electric

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current applied at a distance using a

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long loop of wire and a strong battery.

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At the time our understanding of

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information was in its infancy.

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People were thinking about information and a

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message as the number of letters in a

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message so the goal was intuitive:

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who could come up with the fastest way to

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transmit letters and whoever had the

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fastest system would therefore reduce

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the cost per message for the sender

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using this system.

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And a gold mine was waiting for whoever

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got there first.