This story is part of “How Does It Work?” — The Better India’s series that takes the everyday things you see, use, and rely on, and uncovers the clever technology, design and sustainable thinking that make them work better. From the objects in your home to the systems around you, we break down the ideas behind them in simple, easy-to-understand language. Because innovation isn’t always about futuristic machines or complicated technology. Sometimes, it’s hiding in the things we use every day.
A few months ago, concerns around LPG availability and rising cooking fuel costs had many Indian households looking for alternatives in the kitchen. For some, the answer was an appliance that had already been sitting on the countertop: the induction cooktop.
Unlike a gas stove, it does not need a flame. Unlike a traditional electric stove, it does not rely on a glowing-hot coil to transfer heat to a vessel. Instead, it uses something we cannot see but use every day: electromagnetic fields.
So, how does a flat glass surface heat a pan, boil water and cook a meal? The answer lies in a little-known interaction between electricity, magnetism and metal.
It begins with a coil beneath the glass
Look beneath the smooth glass surface of an induction cooktop, and you will find a tightly wound coil of copper wire. When the stove is switched on, an alternating electric current flows through this coil.
Unlike a steady current, alternating current repeatedly changes direction. This movement of electricity creates a rapidly changing magnetic field around the coil.
When suitable cookware is placed on the cooking zone, the changing magnetic field passes through the glass and interacts with the metal base of the pan.
Photograph: (India Today)
The field is invisible, but it is strong enough to interact with certain types of cookware placed above it. The glass surface itself does not produce the heat needed to cook food. Instead, it allows the magnetic field to pass through and reach the pan.
The pan becomes the heating element
This is where induction cooking gets interesting.
Place a pan made of a suitable magnetic material, such as iron, cast iron or magnetic stainless steel, on the cooking zone. The changing magnetic field passes into the metal base of the pan.
According to the principle of electromagnetic induction, a changing magnetic field can generate electric currents in a nearby conductor. Inside the pan, these currents move in swirling loops. They are called eddy currents.
You cannot see these currents, and they do not travel through a wire connected to the pan. They are generated directly inside the metal by the magnetic field produced beneath it.
But how does moving electricity turn into heat?
Resistance turns electricity into warmth
Every metal offers some resistance to the movement of electric current. When the eddy currents circulate through the base of the pan, they encounter this resistance.
That resistance converts electrical energy into thermal energy, or heat. The bottom of the pan warms up, and that heat spreads through the vessel to the food or water inside it.
As these currents encounter resistance within the metal, electrical energy is converted into heat, warming the pan and cooking the food inside it.
Photograph: (Instagram/@thebetterindia)
In simple terms, the induction cooktop does not heat the pan from the outside. It uses a changing magnetic field to generate tiny electric currents within the pan itself, and the pan’s resistance turns those currents into heat.
This is why the cookware effectively becomes its own heating element.
Why does the glass surface stay relatively cool?
If the pan gets hot, why does the glass beneath it not become equally hot?
The magnetic field passes through the glass, which is not the main target of the heating process. Since glass does not conduct electricity like the metal base of the pan, it does not develop the same kind of eddy currents that generate heat in suitable cookware.
As a result, the cooktop’s surface generally remains much cooler than the pan while the stove is operating. However, it is not completely immune to heat. The hot vessel transfers some warmth back to the glass, so the cooking zone can still become hot during or after use.
The cooktop also uses sensors and electronic controls to regulate power and detect suitable cookware. If you remove the pan, many induction stoves automatically reduce or stop heating.
A small change that makes cooking smarter
Induction cooking is a useful example of how science can turn an everyday appliance into a more efficient solution. By directing energy into the cookware instead of relying on a flame or a continuously heated coil, it reduces heat loss to the surrounding air and offers precise temperature control
From an invisible magnetic field to a steaming meal, induction cooking is everyday science at work. Photograph: (Instagram/@thebetterindia)
It also eliminates the need to burn LPG during cooking, making it a practical alternative for households looking to reduce their dependence on conventional cooking fuels.
The next time a pan begins to boil on a seemingly ordinary glass surface, remember: beneath it, a copper coil is creating an invisible magnetic field; the field is inducing currents in the pan, and electrical resistance is doing the rest.
No flame, no glowing coil, just electricity and magnetism working together to turn a pan into a source of heat.
