July 22, 2026 • 12 mins
Instead of putting a pan on a source of heat (like a gas burner or electric element), an induction cooktop creates heat in the pan itself thanks to the principles of electromagnetism and resistance. Learn how it works -- plus the pros and cons of the technology -- in today's episode of BrainStuff, based on this article: https://home.howstuffworks.com/induction-cooktops.htm/printable
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Speaker 1 (00:01):
Welcome to brain Stuff, a production of iHeartRadio, Hey brain
Stuff Lauren Bobobomb. Here the principle of cooking food in
a pot or pan atop a heat source that hasn't
changed much since the dawn of cookware. The cookware acts
as the intermediary between the heat source and the food.
(00:24):
The main weakness here is that the heat source, be
it an open fire or a tiny gas flame or
an electric element, only directly heats the part of the
cookware that touches it. The rest of the cookware is
warmed by heat conduction, and as a result, the food
receives different amounts of heat from different parts of the
(00:44):
pot or pan. This is why with conventional heating elements
like an electric or gas stovetop, we have to rely
on the slow process of convection to heat a stew
all the way through, and have to stir some foods
constantly to prevent them from from burning in the pan.
Electric elements, in particular, tend to toggle on and off
(01:05):
to keep an overall steady temperature, which can lead to hotspots.
This is why recipes for delicate sauces like chocolate ganache
or a hollandaise traditionally want you to heat your ingredients
in a vessel over steaming water instead of directly on
a cook top. This conducts heat to the floor of
the pan more evenly, helping you reduce the risk of scorching, boiling, separation,
(01:30):
and other heartaches. And this has been what's up for millennia.
But within the past fifty years or so, a new
use of technology has provided a different option. Induction cook
tops help you heat food more evenly by cutting out
the middleman and turning the cookware itself into the source
of heat as long as that cookware is made of
(01:52):
the right stuff. Iron or steel pans work well, but
pretty much any other material that you put on the
cook top, like aluminum or pyrex or your hand won't
get hot. Induction cooktops also feature precise temperature control and
the capacity for very low temperature settings, all while working
more efficiently and producing less waste heat in your kitchen.
(02:16):
An induction cooktop can do all of this because of
the properties of electricity and magnetism. Magnets are not magical.
We know how they work, though it is true that
the force that governs them electromagnetism, is many times stronger
than gravity. The suspension of a maglev train above its
track is a striking example of this point. Electricity and
(02:40):
magnetism can affect each other without physical contact through electromagnetic fields.
This is what's happening in induction. Cooking a circuit with
an alternating current flowing through it inside the stovetop generates
current in another circuit in the pan simply by placing
the pan nearby. The pan converts that current into heat.
(03:02):
But okay, that's a lot. Let's unpack it. There are
some basic principles of electromagnetism at work here. Every electric
current has a magnetic field surrounding it. An alternating current
is an electric current that periodically reverses direction, which is
useful because that means that its magnetic field also fluctuates.
(03:25):
This is useful because fluctuating magnetic fields induce currents to
start flowing and electrically conducive materials placed within those fields.
Alternating current is the type of current used to send
power through lines to homes and businesses and libraries and
everything else on the grid. Because of these properties, induction
(03:46):
allows high voltage current from power lines to be stepped
down through passive conductive devices called transformers that make the
current low voltage and safe enough for actual use by
you and all of your appliances. Induction is also the
principle that makes everything from electric generators to electric toothbrushes possible.
(04:08):
For induction cooking, it's important to remember one more principle,
electrical resistance. You know, some materials are good at conducting electricity,
and some materials conducted poorly or resist it. Induction cooking
works because iron and steel are magnetic, so you can
induce current in them, but they are also just complete
(04:30):
crud at conducting electricity, so they convert that current to
heat and heat up like almost instantly. A lower current
will create less heat, a higher current will create more,
and you can use the controls on the induction element
to turn it up or down. I find it useful
to think about light bulbs when considering electric current flow
(04:51):
and resistance. An incandescent light bulb on a cord is
a great example of both. You've got current flowing to
it nice through the conductive wire in that cord, but
inside the bulb the current encounters a different kind of wire,
a filament that resists flow like all heck, and as
a result, it gives off visible light and heat. So
(05:15):
that's a simple example of how you can harness the
flow and resistance of a current in different materials. An
induction cooktop is a little more complicated. It contains an electromagnet,
a type of magnet in which you create the magnetic
field by introducing electric current to the device, So you
can turn the magnet on and off, and you can
(05:36):
make the magnetic field weaker or stronger with the amount
of current you apply. In the case of an induction
cooktop element, your electromagnet is probably a spiral of tightly
coiled copper cable. So you turn the element on and
it sends an alternating current through the cable, which creates
an alternating magnetic field above the cable, which is near
(05:59):
the surface of the cook top, just below a protective
finish made of glass and ceramic, you know, the same
as what you'd have on some conventional electric cooktops. Well,
when you put something that is not magnetic in that
alternating magnetic field on that cook top, nothing happens. You
can toss a stack of paper on there, or put
your big silly hand right on it, and you won't
(06:20):
feel any heat because there isn't any unless you happen
to be wolverine, and we've decided that adamantium is ferromagnetic. Anyway,
when you put something that is magnetic in that field,
like a ferromagnetic cast iron, stainless steel, or carbon steel pan,
the field will induce an electrical current in the material
(06:42):
of the pan. Because the field is alternating, the current
in the pan flows or kind of swirls like an
eddy or it tries to, but the metal resists it,
and thus it creates heat. In order to create enough
heat to be useful for cooking, you need a very
high rate of change in the magnetic field, and this
(07:04):
a high frequency of alternating current flowing through the electromagnet.
Induction cooktops accomplish this via a series of electronic devices
that increase the current and frequency while also protecting your
home and appliance wiring, including a transformer, rectifier, and inverter.
When the current finally reaches the induction coil, it's been
(07:26):
increased to a frequency roughly a thousand times higher than
that of a wall socket. But practically all of this
means that not all cookwar will work with induction devices.
A ferromagnetic materials work because they are susceptible to magnetic fields. Basically,
because their electrons are unbalanced. Any given atom in them
(07:48):
will have an upspin or a down spin, and thus,
in certain circumstances can behave like a magnet. Some stainless
steel even will contain too much nickel for this to work.
If you've got a favorite pan and you're not sure
what it's made of, you can check whether it'll work
on an induction cooktop by taking a normal old fridge
magnet and trying to stick it to the bottom of
(08:09):
the pan. If you've got a newer pot made of
a copper or whatever, you might want to check. Some
manufacturers have started adding an iron plate to the bottom
of their non ferrost cookware to allow them to work
with induction. If the magnet sticks, you're good to go.
If it falls off, you're out of luck. Also, some
(08:30):
induction cooktops have built in detectors that will tell you
if a potter pan is appropriate. Oh, and they usually
include an indicator light to tell you when the unit
is on. Since you won't feel any heat, so this
is certainly a clever way of producing heat for cooking,
but like all technologies, it does have its pros and cons.
(08:52):
Induction cooktops are more energy efficient. It's estimated that gas
cooktops are able to convert about thirty eight percent of
their energy in to the food in the pan. Electric
can convert about seventy percent, Induction can convert over eighty percent.
Induction cooktops also heat faster than gas or electric, and
(09:13):
as precisely or more so than gas. Induction is also
safer because these ceramic glass cook top doesn't get hot,
you reduce the risk of burns or fires, though note
that the surface can get warm due to heat transfer
from the pan. Gas in particular causes indoor air pollution
and is volatile. Misalignments and other issues can cause gas
(09:36):
to leak into a home, creating serious hazards. Induction surfaces
are also easier to clean than exposed electric coils or
gas grates. Downsides include that it's just a different technology
that you have to get used to using. It can
heat things some fifty percent faster, so you've got to
watch stuff at first and adjust your expectations. Induction units
(10:00):
are still more expensive than conventional units as well, enough
so that as of now you're unlikely to make up
the cost difference in energy savings. Induction does tend to
operate with a bit of noise, a buzz or vibration,
and or some fan noise. Some are designed with fans
in the base, so you might not be able to
install them over an existing oven and would have to
(10:22):
replace the whole range. If you are replacing an existing
cooktop or range with induction, check with an electrician to
be sure that your wiring, voltage and ambriage can handle
the load. Improper installation can also interfere with radio or
television reception, and experienced electrician can help you avoid that
or constantly tripping your breakers or worse. There are some
(10:46):
other rare safety issues because this is an electromagnetic device.
If you have a pacemaker or something similar, you might
want to check with your doctor first. You certainly don't
want to create any interference with that. In a similar
but less serious vein, you probably won't be able to
use a digital thermometer to read the contents of a
pan while the induction unit is on. Cooktops using induction
(11:10):
technology were experimented with as early as the nineteen thirties,
but didn't hit the consumer market until the nineteen seventies.
It's caught on faster in Europe and Asia, but the
market is becoming more competitive in the US too, especially
as fuel expenses rise and with legislation in places like
California moving away from new gas installations, it's expected that
(11:33):
more people and businesses will be induced to adopt induction.
Today's episode is based on the article how induction cooktops
work on how stuffworks dot Com, written by Nicholas Jervis.
Brain Stuff is production of iHeartRadio in partnership with how Stuffworks.
Dot Com is produced by Tyler Klain. For more podcasts
(11:55):
from my heart Radio, visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to your favorite shows. Hmm
Welcome to brain Stuff, a production of iHeartRadio, Hey brain
Stuff Lauren Bobobomb. Here the principle of cooking food in
a pot or pan atop a heat source that hasn't
changed much since the dawn of cookware. The cookware acts
as the intermediary between the heat source and the food.
(00:24):
The main weakness here is that the heat source, be
it an open fire or a tiny gas flame or
an electric element, only directly heats the part of the
cookware that touches it. The rest of the cookware is
warmed by heat conduction, and as a result, the food
receives different amounts of heat from different parts of the
(00:44):
pot or pan. This is why with conventional heating elements
like an electric or gas stovetop, we have to rely
on the slow process of convection to heat a stew
all the way through, and have to stir some foods
constantly to prevent them from from burning in the pan.
Electric elements, in particular, tend to toggle on and off
(01:05):
to keep an overall steady temperature, which can lead to hotspots.
This is why recipes for delicate sauces like chocolate ganache
or a hollandaise traditionally want you to heat your ingredients
in a vessel over steaming water instead of directly on
a cook top. This conducts heat to the floor of
the pan more evenly, helping you reduce the risk of scorching, boiling, separation,
(01:30):
and other heartaches. And this has been what's up for millennia.
But within the past fifty years or so, a new
use of technology has provided a different option. Induction cook
tops help you heat food more evenly by cutting out
the middleman and turning the cookware itself into the source
of heat as long as that cookware is made of
(01:52):
the right stuff. Iron or steel pans work well, but
pretty much any other material that you put on the
cook top, like aluminum or pyrex or your hand won't
get hot. Induction cooktops also feature precise temperature control and
the capacity for very low temperature settings, all while working
more efficiently and producing less waste heat in your kitchen.
(02:16):
An induction cooktop can do all of this because of
the properties of electricity and magnetism. Magnets are not magical.
We know how they work, though it is true that
the force that governs them electromagnetism, is many times stronger
than gravity. The suspension of a maglev train above its
track is a striking example of this point. Electricity and
(02:40):
magnetism can affect each other without physical contact through electromagnetic fields.
This is what's happening in induction. Cooking a circuit with
an alternating current flowing through it inside the stovetop generates
current in another circuit in the pan simply by placing
the pan nearby. The pan converts that current into heat.
(03:02):
But okay, that's a lot. Let's unpack it. There are
some basic principles of electromagnetism at work here. Every electric
current has a magnetic field surrounding it. An alternating current
is an electric current that periodically reverses direction, which is
useful because that means that its magnetic field also fluctuates.
(03:25):
This is useful because fluctuating magnetic fields induce currents to
start flowing and electrically conducive materials placed within those fields.
Alternating current is the type of current used to send
power through lines to homes and businesses and libraries and
everything else on the grid. Because of these properties, induction
(03:46):
allows high voltage current from power lines to be stepped
down through passive conductive devices called transformers that make the
current low voltage and safe enough for actual use by
you and all of your appliances. Induction is also the
principle that makes everything from electric generators to electric toothbrushes possible.
(04:08):
For induction cooking, it's important to remember one more principle,
electrical resistance. You know, some materials are good at conducting electricity,
and some materials conducted poorly or resist it. Induction cooking
works because iron and steel are magnetic, so you can
induce current in them, but they are also just complete
(04:30):
crud at conducting electricity, so they convert that current to
heat and heat up like almost instantly. A lower current
will create less heat, a higher current will create more,
and you can use the controls on the induction element
to turn it up or down. I find it useful
to think about light bulbs when considering electric current flow
(04:51):
and resistance. An incandescent light bulb on a cord is
a great example of both. You've got current flowing to
it nice through the conductive wire in that cord, but
inside the bulb the current encounters a different kind of wire,
a filament that resists flow like all heck, and as
a result, it gives off visible light and heat. So
(05:15):
that's a simple example of how you can harness the
flow and resistance of a current in different materials. An
induction cooktop is a little more complicated. It contains an electromagnet,
a type of magnet in which you create the magnetic
field by introducing electric current to the device, So you
can turn the magnet on and off, and you can
(05:36):
make the magnetic field weaker or stronger with the amount
of current you apply. In the case of an induction
cooktop element, your electromagnet is probably a spiral of tightly
coiled copper cable. So you turn the element on and
it sends an alternating current through the cable, which creates
an alternating magnetic field above the cable, which is near
(05:59):
the surface of the cook top, just below a protective
finish made of glass and ceramic, you know, the same
as what you'd have on some conventional electric cooktops. Well,
when you put something that is not magnetic in that
alternating magnetic field on that cook top, nothing happens. You
can toss a stack of paper on there, or put
your big silly hand right on it, and you won't
(06:20):
feel any heat because there isn't any unless you happen
to be wolverine, and we've decided that adamantium is ferromagnetic. Anyway,
when you put something that is magnetic in that field,
like a ferromagnetic cast iron, stainless steel, or carbon steel pan,
the field will induce an electrical current in the material
(06:42):
of the pan. Because the field is alternating, the current
in the pan flows or kind of swirls like an
eddy or it tries to, but the metal resists it,
and thus it creates heat. In order to create enough
heat to be useful for cooking, you need a very
high rate of change in the magnetic field, and this
(07:04):
a high frequency of alternating current flowing through the electromagnet.
Induction cooktops accomplish this via a series of electronic devices
that increase the current and frequency while also protecting your
home and appliance wiring, including a transformer, rectifier, and inverter.
When the current finally reaches the induction coil, it's been
(07:26):
increased to a frequency roughly a thousand times higher than
that of a wall socket. But practically all of this
means that not all cookwar will work with induction devices.
A ferromagnetic materials work because they are susceptible to magnetic fields. Basically,
because their electrons are unbalanced. Any given atom in them
(07:48):
will have an upspin or a down spin, and thus,
in certain circumstances can behave like a magnet. Some stainless
steel even will contain too much nickel for this to work.
If you've got a favorite pan and you're not sure
what it's made of, you can check whether it'll work
on an induction cooktop by taking a normal old fridge
magnet and trying to stick it to the bottom of
(08:09):
the pan. If you've got a newer pot made of
a copper or whatever, you might want to check. Some
manufacturers have started adding an iron plate to the bottom
of their non ferrost cookware to allow them to work
with induction. If the magnet sticks, you're good to go.
If it falls off, you're out of luck. Also, some
(08:30):
induction cooktops have built in detectors that will tell you
if a potter pan is appropriate. Oh, and they usually
include an indicator light to tell you when the unit
is on. Since you won't feel any heat, so this
is certainly a clever way of producing heat for cooking,
but like all technologies, it does have its pros and cons.
(08:52):
Induction cooktops are more energy efficient. It's estimated that gas
cooktops are able to convert about thirty eight percent of
their energy in to the food in the pan. Electric
can convert about seventy percent, Induction can convert over eighty percent.
Induction cooktops also heat faster than gas or electric, and
(09:13):
as precisely or more so than gas. Induction is also
safer because these ceramic glass cook top doesn't get hot,
you reduce the risk of burns or fires, though note
that the surface can get warm due to heat transfer
from the pan. Gas in particular causes indoor air pollution
and is volatile. Misalignments and other issues can cause gas
(09:36):
to leak into a home, creating serious hazards. Induction surfaces
are also easier to clean than exposed electric coils or
gas grates. Downsides include that it's just a different technology
that you have to get used to using. It can
heat things some fifty percent faster, so you've got to
watch stuff at first and adjust your expectations. Induction units
(10:00):
are still more expensive than conventional units as well, enough
so that as of now you're unlikely to make up
the cost difference in energy savings. Induction does tend to
operate with a bit of noise, a buzz or vibration,
and or some fan noise. Some are designed with fans
in the base, so you might not be able to
install them over an existing oven and would have to
(10:22):
replace the whole range. If you are replacing an existing
cooktop or range with induction, check with an electrician to
be sure that your wiring, voltage and ambriage can handle
the load. Improper installation can also interfere with radio or
television reception, and experienced electrician can help you avoid that
or constantly tripping your breakers or worse. There are some
(10:46):
other rare safety issues because this is an electromagnetic device.
If you have a pacemaker or something similar, you might
want to check with your doctor first. You certainly don't
want to create any interference with that. In a similar
but less serious vein, you probably won't be able to
use a digital thermometer to read the contents of a
pan while the induction unit is on. Cooktops using induction
(11:10):
technology were experimented with as early as the nineteen thirties,
but didn't hit the consumer market until the nineteen seventies.
It's caught on faster in Europe and Asia, but the
market is becoming more competitive in the US too, especially
as fuel expenses rise and with legislation in places like
California moving away from new gas installations, it's expected that
(11:33):
more people and businesses will be induced to adopt induction.
Today's episode is based on the article how induction cooktops
work on how stuffworks dot Com, written by Nicholas Jervis.
Brain Stuff is production of iHeartRadio in partnership with how Stuffworks.
Dot Com is produced by Tyler Klain. For more podcasts
(11:55):
from my heart Radio, visit the iHeartRadio app, Apple Podcasts,
or wherever you listen to your favorite shows. Hmm
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