Definition
An atom or molecule that carries an electric charge because it has lost or gained one or more electrons. An atom that loses electrons becomes a positive ion; one that gains electrons becomes a negative ion.
Plain English
A particle that is electrically charged because its number of electrons no longer matches its number of protons.
Context Anchor
Seen in aircraft maintenance discussions involving batteries, corrosion, electrical charge, and chemical reactions.
Derivation
From the Greek 'ion,' meaning 'going.' Early scientists noticed these charged particles move toward an electrode when a voltage is applied — they 'go' somewhere. The name captures the behaviour that makes ions matter electrically.
Why Pilots Care
Ion movement is what carries current in batteries and what drives many corrosion reactions on airframes. Understanding ions helps make sense of how aircraft batteries store and deliver power, and why dissimilar metals in contact with moisture corrode.
Grounding Statement
If moisture is sitting on metal, charged particles in that moisture can help electricity move and can support corrosion.
Intuition Check
An ion is not just any tiny particle. It specifically means a particle with an electric charge.
Example Sentence 1
When the battery discharges, ions move through the electrolyte between the plates, producing the current that powers the aircraft's electrical system.
Example Sentence 2
During charging, positive ions travel to the negative plate inside the aircraft battery.