Electricity, late 19th century

Electricity – a general term that covers a variety of phenomena resulting from the presence and flow of electric charge. These include lightning and static electricity, but also electromagnetic field and electromagnetic induction.

Explore – What’s the problem? Why?

Examples – What can it do? * solutions

  • Static electricity (images) – The door knob provides a shock after scuffing your feet on the carpet. Sparks fly when you pull the wool sweater off. The silk handkerchief exhibits a static cling to a cotton shirt in the dryer. We’re amazed by the spectacle of a lightning strike during a storm. These are familiar phenomenon that pertain to static electricity.

Engineering – How did they do that? How does it work?

In general usage, the word ‘electricity’ is adequate to refer to a number of physical effects. For science and engineering, use these more precise terms:

  • Electric charge – a property of some subatomic particles, which determines their electromagnetic interactions. Electrically charged matter is influenced by, and produces, electromagnetic fields.
  • Electric current – a movement or flow of electrically charged particles, typically measured in amperes.
  • Electric field – an influence produced by an electric charge on other charges in its vicinity.
  • Electric potential – the capacity of an electric field to do work, typically measured in volts.
  • Electromagnetism – a fundamental interaction between the electric field and the presence and motion of electric charge.

Lightning (images) – There are many different types of lightning. There is cloud-to-cloud lightning, cloud-to-ground lightning, ball lightning, and even other forms of lightning that are instigated by volcanic eruptions, forest fires or dust storms. All these types of lightning have one thing in common: the build-up and ultimate release of static electric charge from a cloud to the earth. The most common form of lightning is cloud-to-cloud lightning. The electric charge moves from one cloud in the sky to another cloud some distance away. In this form of lightning, there is never any discharging to the Earth. Estimates suggest that there are as many as 100 worldwide cloud-to-cloud lightning bolts every second.

  • A lightning rod or lightning conductor – a single component in a lightning protection system. The actual rooftop lightning rod is a metal strip or rod, usually of copper or aluminium.

Direct current

Alternating current (AC) – an electrical current whose magnitude and direction vary cyclically, as opposed to direct current, whose direction remains constant. The usual waveform of an AC power circuit is a sine wave, as this results in the most efficient transmission of energy. However in certain applications different waveforms are used, such as triangular or square waves.

Power and light

Infrastructure or grid – distribution

  • generation
  • transmission
  • regulation – federal oversight of bulk distribution and state oversight of regional transmission and local delivery
  • reliability, quality
  • security
  • growth, demand, capacity – internet services are creating increasing demand for capacity and reliability as more business, government and personal communications and work are done online.


  • Self-healing power grid – a smart grid with the ability to anticipate, respond to and isolate damage could mitigate the impact and speed recovery from damage to physical infrastructure during severe weather and other disasters.
  • Trying to Energize the Push for a Smart Grid – ScienceFriday podcast – For years, electrical experts have been calling for a “smart grid” that could better sense and adapt to changing conditions, from electrical outages to shifts in power consumption. Massoud Amin, referred to by some as the “father of the smart grid,” talks about how and why the country should improve its aging electrical infrastructure.

Alternative power sources – research and development

  • Underwater Kites To Harness Liquid Breezes For Power – small tethered, undersea kites that can “fly” quickly in currents of the Gulf Stream, the massive underwater current flowing from the Gulf of Mexico into the Atlantic Ocean. That power potential is estimated at about 20 gigawatts, or about 10 nuclear power plants. Like wind turbines can convert moving air into electricity, there is the potential to transform these liquid ‘breezes’ into power

Engineering ideas

Do it
Here are some challenges for you to work on…

  • Electric Field Hockey – Learn how charges can attract and push away from one another. Play hockey with electric charges. Use positively and negatively charged points to try and guide a positively charged (puck) into the goal. Place charges on the ice, then hit start to try to get the puck in the goal. View the electric field. Trace the puck’s motion. Make the game harder by placing walls in front of the goal.
  • Static Electricity Experiment – Use balloons to create static electricity while learning about positively and negatively charged particles with this fun experiment.
  • Electricity – fill in the blank word puzzle

Learn more…