Jolena, Emil and Billy stood on the bench for a while after the plane had gone, wondering about how planes could fly without flapping their wings.
"Let's ask Mandy!" they all said at once.
When they got home, they took off their jackets and put them away. They were ready to look for Mandy.
Mandy knows a lot of things about how the world works, and if there's something she doesn't know, she knows how to find out. The dolls found Mandy in the living room, knitting. She looked up when they came in.
"Mandy," Emil said as the dolls had climbed up on the couch, "We were wondering how airplanes can fly without flapping their wings."
"Yes," Jolena agreed. "We were just at the airstrip watching a plane take off. We started to wonder about it."
Mandy moved her knitting to the couch and put her glasses on the top of her head. "Sure," she said. "It will be easier, though, if we see what a plane looks like while we talk about it. Let's go over to the table," she suggested. "I think there's some paper and a pencil there."
The dolls slid down off the couch, walked into the dining room and climbed up on two of the chairs. Mandy picked up a piece of paper and a pencil from the supplies that had been set out for the dolls' homework and, after putting her glasses back on her face, quickly drew a picture of an airplane. It was an amazingly good drawing for a doll who was not an artist, but Mandy has a great imagination!
"Let's start with the four forces," she suggested, as the other three dolls made sure their listening ears were in place. (Listening ears are inside your head. They are what help you pay attention, so Emil's listening ears work just as well as Billy's and Jolena's.)
"The Four Forces," Billy said. "That sounds like a team of superheroes!"
"They sort of are superheroes," Mandy agreed, "and they have to work together. Without working together, they could never get planes off the ground! Let's take these superheroes one at a time," she continued. "First, do you know why we don't just float off into space? What holds us to the earth?"
"I know that," Jolena said, raising her hand. "It's gravity. I learned about it in ski school, and then at regular school. It's what makes us heavy. It's why we can ski downhill but have to ride the lift back up."
"Very good," Mandy agreed. "Now, do you know what that heaviness is called?" she asked.
"Um," Billy said, "is that what you call weight?"
"Yes," Mandy agreed. "Weight is the force that causes gravity to pull us down, and that's one of the four forces I was talking about." Mandy drew an arrow going down under the airplane to show that it was affected by weight. Then she waited, while the other three dolls thought about that.
"There's another force that can lift us up," she said, drawing an arrow pointing upward above the airplane. "Now," she asked, "what do you think that force is called?"
"Happy thoughts" Jolena asked? "Happy thoughts lift us up."
"Well," Mandy said, "happy thoughts lift us up on the inside, and a pilot who has happy thoughts will probably find it easier to fly the plane, but happy thoughts won't make the plane fly if we can't use the four forces correctly."
"I don't suppose the force that lifts could be called lift," Emil conjectured. "That would be too simple."
"That is the word for it, actually," Mandy agreed, "and it is simple. Lift is the force that makes something go up. It's what helps hold an airplane in the air." Mandy used the pencil to point to the arrow she had just drawn.
"Weight and lift can work against each other," Mandy explained, "but when the plane is built right, the way the body and the wings are shaped make weight and lift work together." She paused and thought for a moment. "How can I demonstrate this?" she asked herself.
Suddenly Mandy said, "Come, I just thought of a way I can show you!" She slid down from the chair and walked to the kitchen. She turned at the door to the kitchen and beckoned the other dolls to follow, because they were still at the table.
When they had pulled some stools over to the sink, Mandy took off her shoes, so they wouldn't get wet. Then she got into the sink and filled a pan with water while the other dolls gathered around.
Next, Mandy went over to the tools pitcher next to the stove and pulled out the rice paddle. "This is sort of like an airplane wing," Mandy said to herself. Then she came back to the sink.
Mandy put the paddle into the water and moved it gently back and forth. "This will work," she said, clearly pleased. "When you move the paddle through the water, back and forth like this, then tip the paddle up slightly as you move it through the water in that direction, you can feel it try to go up."
Then she let the other dolls try. Each one had a try, one after another, so they could feel feel the pressure of the water making the paddle go up.
The dolls left the water for The Writer to use to water the plants, so it wouldn't be wasted. Mandy's feet were wet, so Jolena handed her a towel to dry off her feet before she put her shoes back on.
"My ski teacher told us the air is just like water, only thinner," Jolena said while Mandy was drying off.
"The water is a liquid," Emil put in, remembering what he learned in school, "and the air is a gas. A gas is thinner, I think."
The dolls went back to the dining room. "Yes," Mandy agreed. "It works almost the same way in both water and air," she said as the they climbed back up on the dining room chairs, "only it takes more to stay up in the air than it does to stay up in water. Planes have propellers or jet engines to make them move, and it's the only way they can fly because they are heavier than the air. Planes have to keep moving, and so do birds, to stay up in the air."
"What about hummingbirds?" Jolena asked. "They can float in one place in the air while they eat from a flower."
"And what about helicopters?" Billy asked. "They can stay in one place, too."
"Hummingbirds are able to hover (HUH-ver), or stay in one place," Mandy replied, "but their wings have to keep moving. Hummingbird wings can move so fast you almost can't see them."
"Helicopters have wings that spin around over the body," Mandy continued. "It looks like a propeller, but the blades are really specially built wings. You can hardly see them when the helicopter is flying, because they move so fast."
"Both hummingbirds and helicopters are still moving when they appear to float in the air," Mandy explained. "They won't stay in the air if they don't keep moving, and regular airplanes have to keep moving, too, but they have to always move forward to fly."
"You also have to move forward to take off and land," Billy added thoughtfully. "We just saw how the plane had to drive along the landing strip like a car, going faster and faster, still on the ground until it was going fast enough to take off."
"You're right!" Mandy exclaimed, "and that's where the other two forces come in." She pulled the picture of the airplane toward herself and picked up the pencil again.
"That forward movement" Mandy explained, "is created by the engines, and it's called thrust." She drew an arrow pointing away from the front of the plane. "That's the third of the four forces needed for an airplane to fly."
"And the third member of our team of superheroes," Billy said, nodding.
All the dolls agreed with that.
"Finally," Mandy went on, "you need a long runway for an airplane to take off, because, as you saw, it has to have enough speed to overcome the fourth force, which is drag." She drew an arrow pointing away from the back of the airplane.
"What's drag, then?" Billy asked.
"That's the force that holds the airplane back when it's trying to get up in the air and stay here," Mandy replied. "It's made by the air the plane has to get through. It's like what you felt with the paddle in the water."
"I've heard of that!" Jolena exclaimed excitedly. "It's like you're dragging something! My ski teacher said that's why we have to crouch down low and make ourselves as small as possible when we're skiing downhill or down the ski jump. She says it reduces drag."
"That's right," Mandy agreed. "You want to go faster, and drag slows you down. Drag is what makes a parachute work. It slows down the force of weight, so someone can land safely."
"Planes have to be shaped so drag is reduced when they take off and fly." Mandy explained. "Just as weight and lift can work against each other," she continued, "thrust and drag can work against each other. The airplane has to be designed right to get them to work together." Mandy emphasized her point by getting the other dolls to look at the picture of the plane she had drawn.
"For the plane to get off the ground," she said, "thrust has to overcome drag, but the plane is designed to use the four forces to take off, fly and land safely." Mandy put the pencil down, as if to say she was finished with her explanation.
"Our question," Emil pointed out, "was really how planes can fly without flapping their wings. Now that I have an idea of how planes can fly, I'm wondering why birds have to flap their wings. Why don't they just fly the way planes fly."
"Oh, yes," Mandy said. "Thanks for reminding me we weren't done. You see, birds don't often just go up into the air, fly somewhere and then land. They need to take off and land over and over with little space. They don't have engines to give them the thrust they need to get off the ground. They use their wings to go over and under the air over and over, sort of how a swimmer moves through the water." She made motions with her arms that mimicked a swimmer moving through the water.
"Birds," Mandy went on, "use the same techniques as an airplane or a ski jumper when they are already up in the sky or take off from the top of a tree, but they have to be able to take off from the ground, too."
"There's another good reason," Mandy continued, "and a very important one, why airplanes don't flap their wings, even if they could be built to do that."
The other three dolls looked at Mandy.
"Human people are not used to being joggled around," Mandy said, looking around at the others. "They can get used to having the floor move while they're standing or sitting on it, but flapping wings would make the plane bounce up and down much more. It would make all the passengers sick, and not pretend sick, either."
All four dolls wondered what it would be like for being tossed around or shaken up to make you sick. What if it made you sick to fall on the floor or to bounce up and down in the back of a wagon or if someone got upset and threw you across the room?
It was beyond their imaginations, which are very, very good.
"So airplanes don't flap their wings because it would make the passengers sick," Billy said.
"Yes," Mandy agreed. "If I had just answered your question that way, I would have gotten more knitting done."
"But we wouldn't have learned about the four superheroes!" Emil pointed out.
"The Four Forces!" Billy agreed.
Mandy: Götz Happy Kidz Katie 2015
Jolena: Götz Happy Kidz Lena in Aspen
Billy: Götz Happy Kidz Lily at London
Emil: Götz Happy Kidz Emilia
Want to find out more? The Kidz do, too. Mandy's explanation is just an introduction to what enables airplanes to fly. You can learn more, and it's very interesting.
Want to find out more about how the shape of a plane's wings helps lift and drag work together? Check out this NASA link!
Other Resources:
"The Doll's Storybook" is not affiliated with Gotz Dolls USA Inc. or Götz Puppenmanufaktur International GmbH.
Watch for the next story each Friday afternoon at 1:00 PM Pacific Time.
Copyright © 2021, 2024 by Peggy Stuart
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