Delhi, NCR
It was time for Riya to return to Delhi after spending her holidays in Kolkata. The thought of embarking on another solo flight filled her with excitement. She was in a great mood and had packed her clothes herself this time. When she came to Kolkata, her mother had done it for her. But now, having graduated high school and preparing to enter college, she felt it was time to stop depending on others. She would have to carry her own burdens now.
Riya had applied to Delhi University for a degree in Microbiology, submitting the forms online. With her good results, getting into a reputable college shouldn’t be a problem. Counseling was set to begin in a few days.
As soon as Riya finished packing her bag, her brother Arka started pacing around her with a serious expression. It seemed he was silently feeling the pangs of knowing that after spending a few joyful days with his sister, he would soon be alone again. But would he ever admit it? Although Arka was disappointed that Riya wasn’t enrolling in a college in Kolkata, he said, “It’s a good decision to study in Delhi. Now you’ll truly be chasing dreams far from home, just like me! Though not for long. I’ll head abroad for my Ph.D. soon.”
“Why? Someone as brilliant as you, an economist, wouldn’t be of any use to this country? That’s not right at all,” Riya retorted, zipping up her suitcase.
“I never said I’d stay abroad forever. Once I complete my Ph.D., I’ll return and teach here,” Arka replied.
Their conversation was interrupted by the ringing of the doorbell. As Arka walked towards the door, he said, “There’s a surprise for Mom. It’s here. Hold on, let me get it.”
Returning with a large box, Arka announced, “Your flight is tomorrow night. I have to give this to Mom today. We’ll unveil it this evening.”
“What is it? Did you order it online?”
“Tomorrow is Mom’s birthday. I saved up my allowance and bought this induction cooktop as a gift for her. How is it? Tell me!”
“We have one at home too, but it doesn’t get much use. It just sits there collecting dust. I know you can cook on it, but I’ve never tried it myself. Pishi (aunt) is such a busy doctor that it’ll probably just lie idle here as well.”
“Oh no, it won’t stay idle! No one here is as lazy as you. If Mom doesn’t use it, I will.”
“Then you don’t even need to gift it to her. You could have bought something else!” Riya quipped as she adjusted her suitcase handle.
“Let me tell you, Mom doesn’t have much time to spend in the kitchen. If she doesn’t use it, I’ll make use of it myself. Cooking on an induction cooktop is much safer than on a gas stove. If she wants, she can quickly whip up something simple, and if no one’s home, I can make whatever I want. You know how risky outside food can be.”
“I’ve honestly never thought much about induction cooktops before. The one we have just gathered dust. Even our cook refuses to use it. Why do you say it’s so convenient? Explain,” Riya said, setting her work aside and settling down for a chat.
"Then come, let’s open it and see what this new thing looks like. Afterward, we’ll rewrap it properly for the formal unveiling."
Arka carefully freed the induction cooker from its pitch board covering and placed it on the bed. Removing the plastic wrap, he ran his hand over the shiny black plate of the cooker and said,
“This top you see here is made of toughened glass. The glass is specially treated to make it durable so that it doesn’t easily crack or break from impact. It’s also made of heat-resistant material, so it won’t get damaged by heat. Just like you can adjust the flame on a gas burner using a knob, here you can cook at three to four different temperature settings. You can set the cooker to 500, 800, 1000, or 2000 watts.”
“Why is this cooker called an induction cooker?”
“Now that’s the main point, the specialty of the device lies in this. What do you understand by induction? Think of the electromagnetic induction chapter from your twelfth-grade syllabus. In Bengali, of course, it’s called *torit chumbokiyo abesh* (electromagnetic induction).”
“Oh gosh, the Bengali term makes my head spin. I know electromagnetic induction. When electricity flows through an electrical circuit, it creates a magnetic field around it. If another circuit or coil is placed near this magnetic field, current flows through it too.”
“Name another device that uses electromagnetic induction,” Arko said, quizzing her like a teacher.
“A transformer, right?”
“Correct. A transformer has two coils—a primary and a secondary. Both are wire coils. If alternating current flows through one coil, current is induced in the other coil because of the influence of the first. This is how voltage is increased or decreased. Now, who would you thank for this amazing invention?”
“Not you, obviously—Michael Faraday,” Riya replied, laughing.
“Absolutely right. But the man became a physicist without doing any math! I mean, he didn’t even like math. He proudly said, ‘I don’t know math, but I pay mathematicians to work for me in my lab.’ What a genius. Anyway, let’s honor his memory by turning this machine on. What do you say?”
“Turn it on? Why not take it to the kitchen?”
“Not at all. Let’s put it on the study table, plug it into the electrical point, and we’re good to go. The great thing about an induction cooktop is that you can run it anywhere and cook whatever you want. The reason is that it only heats the utensil placed on top and nothing else. But the utensil needs to be flat. Regular round-bottomed woks we use in the kitchen won’t work. The cookware has to be compatible and sit flush with the plate. Otherwise, the machine will turn off on its own. The cooker has a sensor that automatically stops it and beeps to indicate that an unsuitable utensil has been placed.”
“What about glass utensils, like the ones we use in the microwave? Should I get one? Glass sticks perfectly to glass, doesn’t it?”
Arka exclaimed in shock,
"With this kind of reasoning, you want to become a biologist? What did I just say? The utensil must come under the purview of electromagnetic induction. Look at this device—inside it is a primary wire coil. Once you switch it on, current flows through the coil, creating a magnetic field. Our cooking utensil, when placed within this magnetic field, acts like the secondary coil. Alternating current flows through it."
“Oh no! Then you can’t even touch the utensil. It’ll give you a shock!”
"No, it won’t give you a shock. But my strong fingers will land a knock on your head. Don’t you remember? The secondary coil in a transformer generates low-voltage current, right? In an induction cooktop, the voltage in the utensil is about one volt. The current isn’t enough to give a person a shock. When this low-voltage current flows through the utensil, heat is generated due to metallic resistance."
Arka showed the primary wire coil inside the induction cooktop.
"Alright, I get it. Heat is generated due to resistance. Energy conservation principle—electrical energy is converted into thermal energy. Should I give credit to the great scientist Ohm for this?"
"Whether you give him credit or not, the utensil will heat up. But don’t forget James Prescott Joule as well. He demonstrated that when current flows through a metal, electrical resistance generates heat. Since you’ve just joined college, I won’t quiz you with the equations from your twelfth-grade physics textbook. If you’ve forgotten, feel free to glance through it. Anyway, as I was saying, the utensil heats up when current flows through it. Then, you can cook, and the job gets done. The induction cooktop allows you to adjust the heat to high or low voltages at different wattages. Another advantage is that there’s no energy wastage. To explain further, when you place a utensil on a gas burner, some heat escapes from the sides. Here, that doesn’t happen. The glass top doesn’t heat up at all, so no energy is wasted. Only after long cooking does the glass warm slightly due to prolonged contact with the utensil. Look underneath—you’ll see a fan. This fan cools down the induction cooker quickly."
“Is this why cooking is so fast with this device?”
"Exactly. When you cook on a gas burner, a lot of time and energy is spent heating the utensil, but with an induction cooktop, the utensil heats up instantly. The heat remains consistent throughout the cooking process. Another important point is that there’s no risk of accidental fires from clothing catching flame due to negligence. Despite all this, this cooking method isn’t very popular in many countries, including India."
“Can you tell when this device was invented for cooking?”
"The first cooktop was made for cooking in the United States in 1971. Before that, the induction method was used in electrical furnaces. Initially, large machines were used in big hotels to prepare food. Later, they were downsized to make them suitable for kitchens. However, these cooktops were very expensive back then. It took several decades for them to become affordable for ordinary people."
“Let me ask something—plastic or glass utensils can’t be used because they don’t conduct electricity. Iron, steel, or aluminum should work, right? Copper conducts electricity very well, so utensils made of copper should also work, isn’t it?”
"Everything except copper will work. Copper conducts electricity so efficiently that it has almost no resistance, so while electricity flows through it, the utensil doesn’t heat up much. That’s why copper utensils are unsuitable. The best options are steel or high-quality aluminum utensils."
“It’s crystal clear—directly heating the utensil minimizes energy wastage, and cooking gets done quickly. So, for boiling water, should I turn the knob to the highest wattage?”
"Not at all. For boiling water or making tea, 500 watts is sufficient. If you need to fry fish or potatoes, you’ll have to use the highest wattage—2000 watts. However, after sautéing spices, you can add water, cover the pot, and let it cook at 500 watts—it will finish cooking very quickly. The same applies to using a pressure cooker. Keep in mind, not all utensils are suitable for an induction cooktop. Utensil manufacturers mark circular symbols on the bottom of suitable cookware to indicate they are compatible with induction cooking."
"Then when I go back to Delhi, I'll use this for cooking. I understand now how risky it can be if one is careless while cooking with gas."
"That’s why modern induction cooktops automatically shut off if the cookware overheats. Induction heating is much safer than gas. There’s no risk of accidents due to gas leaks in the kitchen. Moreover, since there’s less wasted heat, the kitchen doesn’t become unbearably hot for the cook."
"Alright, let’s pack up the induction cooktop again. We need to surprise Pishi (aunt) in the evening. Giving the gift unwrapped wouldn’t be right." Riya carefully places the new device back in the box.
"And that concludes today’s class for the future scientist. Tomorrow, you’ll spread your wings and fly off to the skies. Unfortunately, I couldn’t test you on cooking skills due to lack of time. But in Delhi, I’ll take the test, understood? Until then, you can practice a bit in your home laboratory. And remember, if you fail, I might still make you stand on the bench at this age."
Riya, bowing dramatically, says,
"As you command, my master!"
