Dear Science,
Does wireless electricity really work? Will it give us cancer?
Will it turn me into a Spider-Man villain? Tell me! I need to
know!
Dear Reader,
Wireless electricity has been around since 1836. Nicholas Callan’s
experiment started it all; when he connected or disconnected a battery
to one loop of wire around an iron bar, he noticed a spark between the
free ends of a second coil of wire wrapped around the same bar. Magic!
The electricity wirelessly transmitted between the coils. It has
everything to do with the funny relationship between electricity and
magnetism. Electrical currents make magnetic fields (thanks William
Sturgeon) and changing magnetic fields can induce currents in wires
(thanks Michael Faraday). When Nick connected or disconnected the
battery from the first coil of wire, the magnetic field (carried down
the iron rod) changed. When the magnetic field changed around the
second coil of wire, an electric current was created, causing the
spark. Every power plant still works by changing a magnetic field
around coils of wire. Wireless electricity in your home is the same
process on a smaller scale. Induction cooktops and wireless chargers
for electric toothbrushes and cell phones all work by changing a
magnetic field in one place to create a current in another.
So, if the technology is so old, why do we still have a rat’s nest
of wires to power everything? Because magnetic fields rapidly lose
strength with distance. As radio waves, a tiny bit of power can be
transmitted huge distances, but getting enough power to run a lightbulb
over a long distance is impractical; wires are just more efficient.
Even newer technologies—focused microwaves, or lasers—still
have not made wireless electricity practical. We went on to create
radio, television, and wireless Ethernet instead—where tiny
amounts of induced current are used to communicate rather than power.
As a result, we live in a world bathed in current-inducing
electromagnetic fields.
So, are we all going to die from radio-induced cancer? For every
study showing a weak connection between exposure to electromagnetic
fields and cancer, another exists showing a lack of connection; any
risk must be pretty tiny. Science finds it amusing when people
blissfully engage in a wide variety of life-shortening
activities—smoking, eating trans-fat fried foods—only to
stay awake at night fretting over electromagnetic fields. You are much
more likely to die from someone gabbing on a cell phone while driving a
car than from testicular cancer from your pocketed cell phone.
So, sorry, no superpowers will come forth from wireless electricity.
The War of Currents, fought between Edison, Tesla, and
Westinghouse—involving artificial lightning, Niagara Falls, and
ghastly intentional electrocutions of livestock and
prisoners—remains the only superhero battle in electricity.
Galvanizingly Yours,
Science
Send your science questions to dearscience@thestranger.com.
