How Do Ceiling Fans Work?

0:00How do ceiling fans work? Hi! Welcome to Curious Kids Every Day! I'm Josh! How are you doing today? It's so good to hear from you. Hey, does the room you're in right now have a ceiling fan? Or if you're listening to this in the car right now, does your living room have a ceiling fan or your bedroom? ceiling fans are pretty crazy when you really think about it. They seem like they could just spin forever! They circulate air and they stop things from getting too dusty. Have you ever wondered how they work? How do they just keep on spinning like that? I was thinking about this question because I got an email from a curious kid named Josie.

1:04Not my daughter, Josie, a different Josie. Josie wondered, how do ceiling fans work? Inside the fan, there is an electric motor. We just talked about motors the other day in an episode we did about automatic doors. Remember, a motor is a machine that changes electrical energy into motion. The most common kind of motor in a ceiling fan is an induction motor. Can you say induction motor? induction Induction means the motion is created by a changing magnetic push. Yep, a ceiling fan spin is all about magnetic fields.

2:09But what does that mean? Well, when you turn the fan on, electricity flows into coils of wire inside the fan. A coil is just wire wrapped around and around and around and around. When electricity moves through a coil, it creates an invisible magnetic field. The electricity in your house is usually alternating current, which means it changes direction back and forth many times every second. Because the electric current keeps changing, the magnetic field keeps changing too. And that's going to be really important in a second. Now, the motor of a ceiling fan has two main parts. One part stays still and it's called the stator. That's easy to remember, stator.

3:15The stator is in a circle shape. This is where the coils are. The coils are wrapped around in a circle too. And the other part of the motor is called the rotor. And it is the part that rotates. These are easy to remember. The rotor is a circle piece that sits on the inside of the stator. Think about the rotor and the stator like a small donut sitting inside the donut hole of a big donut. Now I want donuts. I'm going to make tomorrow's episode be about donuts. Let me write that down. Anyway, the changing magnetic field from the stator makes the rotor get pulled and pushed around in a circle.

4:17So imagine the little donut sitting inside of the bigger donut and the bigger donut is just sitting perfectly still. But the smaller donut inside of the bigger donut, it's spinning in there. And remember that smaller donut, that's the rotor. It's made of conductive metal bars that react to the magnetic field created by the coils in the stator, the bigger donut. I really want a donut. The spinning rotor on the inside is connected to the fans shaft. And the shaft is connected to the blades. So when the rotor turns, the blades turn too. It's all about magnetic push and pull. The alternating current and the magnetic field work together to create this perfect dance.

5:20That's why when you turn on a ceiling fan, it takes a little bit to reach the right speed. The magnetic field and all the pushing and pulling takes a little bit of time to get started. But as soon as you flip the switch, that's why you start to see motion. It's a magnetic field you've just created. It's like if you're holding a magnet and you place it close to something that is attracted to magnets. What is that thing that's sitting still? What does it start to do when you put a magnet near it? Right, it moves. Magnets create motion. And here's what's happening when you adjust the speed of the fan. Have you ever wondered why when you pull down on that little handle, you can speed up or slow down the fan.

6:20You ever wondered how that works? But what's really happening is pretty simple. You're just adjusting how much electricity is flowing into the stator. And more electricity means a stronger magnetic field. And a stronger magnetic field means more speed. That's almost ceiling fan is. It's a really clever magnetic field, isn't that so cool? As long as electricity keeps flowing, the motor keeps making that magnetic push. But if you turn the electricity off, the magnetic field in the stator gets turned off too. It slows down and stops eventually because of friction. Now we're going to talk about friction and physics next week on the show. But for now, just know that objects in motion want to stay in motion unless an outside force acts on it. That's why if the electricity keeps flowing, the fan keeps spinning.

7:22And when that magnetic field is gone, it slowly stops. And that is the amazing engineering behind how a ceiling fan works. All right, let's have a quick quiz. What is the machine inside a fan that turns electricity into motion? It's called a motor. And what do we call the part of the motor that stays still? It's called the stator, the stator. And what do we call the part of the motor that spins or rotates? We call it the rotor. Let's play true or false. True or false, a ceiling fan can keep spinning even with the power off.

8:22Well, it does keep spinning with the power off for a little bit, but it won't keep spinning. So we'll say true, but also false. True or false, electricity moving through a coil of wire can create a magnetic field. Yep, that's true. Would you rather ride on the blade of a fan or on the wing of an airplane? So the question here is, do you want to spin at a very high speed or do you want to travel through the air at a very high speed? I think I would rather be on the wing of an airplane. Assuming it was perfectly safe for me to do so, that sounds like a fun adventure. All right, let's play a couple of rounds of what am I? What am I? I turn electrical energy into motion.

9:27I have parts that spin and parts that stay still. And I help a fan's blades rotate. What am I? I am the motor. Okay, one more. What am I? You can't see me, but I push and pull. I can be created when electricity moves through a coil. And I help make the motor spin. What am I? I am a magnetic field. Okay, so now we know. A ceiling fan spins because electricity flows into coils. And those coils create a changing magnetic field. And that magnetic push makes the rotors spin. I bet you had no idea that ceiling fans were all about magnetic fields. I sure didn't until I started researching for this episode.

10:28Just goes to show there's always something new to learn. Even about the things that are in the room with you right now that you never really think about. Things like ceiling fans. Isn't that amazing? What kind of question do you think we'll ask tomorrow on curious kids every day? I can't wait to find out. So until then, keep asking questions and stay curious kids. And we've got a few birthdays today. Today is Henry's birthday. Henry is from Ohio and Henry is turning six. Happy birthday, Henry. Bronson is from Florida and Bronson is turning three. Happy birthday, Bronson. Everett is from Virginia and Everett is turning eight. Happy birthday, Everett. Bo is from Missouri and Bo is turning eight. Happy birthday, Bo. Felicity is from Texas and Felicity is turning six. Happy birthday, Felicity. Simon is from Yellowknife, Canada and Simon is turning seven.

11:31Happy birthday, Simon. And Brooks is from Arkansas and Brooks is turning five. Happy birthday, Brooks. To all the grownups listening, if your curious kid wants their birthday mentioned on the show, please visit supportcuriouskids.com and join the Curious Kids Club, that supportcuriouskids.com. See you tomorrow. We're going to talk about donuts.