Tommy Discovers How the Ocean Makes Waves

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    Summer is supposed to be hot, even in the morning. At least that's what Tommy had always believed. So he got a real surprise when he went outside one summer morning and felt that the air was cold. He knew right then that he was going to get more surprises and he knew it was because he wasn't at his own house. In fact, he wasn't even in his own state.

    This summer Tommy's parents had rented a bungalow in a small town by the ocean and Tommy was going to stay there with them for a whole month. It was going to be the first time that Tommy had ever seen and touched a real ocean.

    They had arrived in the middle of the night, so Tommy had not had a chance to look around. He had been too tired anyway and had gone to sleep as soon as he was in bed. He had awakened early, though, dressed himself, and gone outside to explore, discovering immediately that the air was cold and full of fog.

    It was quiet at first, but then Tommy heard a faint roar, a little bit like the sound a jet airplane makes, and then it got quiet again. He was wondering what the sound was when he heard it again and then more silence. He listened for a few more minutes and discovered that whatever was making the sound was being turned on and then turned off again over and over. The sound seemed to be coming from behind the house, so he went to the back yard to investigate.

    The back yard was the smallest that Tommy had ever seen. It ended at a wooden fence only a few feet from the back of the house. Tommy opened the gate in the middle of the fence and saw that the fence was built on the top of a high cliff. On the other side of the gate Tommy saw wooden stairs going down the cliff to the beach. Here and there on the beach big rocks poked up through the sand.

    Then Tommy saw the ocean, water as far as he could see, which wasn't far because of the fog. He saw that the water close to the shore was piled up in a long hill that moved toward the beach. As it came closer to the beach the hill got higher and higher and then its water curled over and spilled onto the beach with a roar. The water backed away from the beach and a moment later another wave came and crashed down in its place. Tommy sat down on the stairs and watched the waves until his mother called him to breakfast.

    After breakfast he asked his mother, "Mom, how does the ocean make waves?"

    "I don't know," his mother replied. "You'll have to ask your father."

    So Tommy went to his father, who was reading the newspaper, and asked, "Dad, how does the ocean make waves?"

    His father put the newspaper down and said, "Well, that question has a very complicated answer. You have to know something about hydrodynamics. You'll understand when you're older." Then he smiled at Tommy, picked up the newspaper, and went back to reading it.

    Tommy went back outside and sat down on the wooden steps where he could watch the ocean make waves. He felt sad inside. He knew that his father wasn't trying to be mean, but Tommy always felt bad when his father used big words like "hydrodynamics" because it made him feel stupid. What made him feel worse was knowing that he could not go to his friends. Talking with them made bad feelings get weaker and good feelings get stronger, but his friends were far away. Tommy felt very sad and very lonely.

    "Well, if the grownups won't help us," he heard a boy's voice say, "then we will just have to find out the answer ourselves."

    Tommy looked around, but he didn't see anybody. He looked around again, more carefully this time, and he saw that there was no place nearby where anyone could hide.

    "You won't find me that way," the voice said. "I'm hiding in a place you can only see with your eyes closed."

    "That's dumb," Tommy said. "Nobody can see anything with their eyes closed."

    "Yes, they can," the voice said. "You do it every night after you go to bed."

    "You mean when I'm dreaming?" Tommy said. Then he got an idea. He stopped talking out loud and said only in his head, "That means you're hiding in my imagination."

    "That's right," the voice said. "Your imagination is a wonderful place to play hide and seek."

    "If you live in my imagination, then you're just something I made up," Tommy said, talking only in his head now. "But I didn't make you up. I don't know who you are. I've never met you before now."

    "My name is Ymmot and I'm what people call an invisible friend," the voice said. "You did make me up just now. You made me up the same way you make up dreams."

    "I don't make up dreams," Tommy said. "They just come to me. And anyway, why would I make you up just now?"

    "You need a friend to talk to and your other friends aren't here," Ymmot said, "so I just came to you like a dream."

    "OK, so what do you want to do?" Tommy asked.

    "Let's figure out how the ocean makes waves," Ymmot said.

    "We can't," Tommy replied. "We have to know something about hydrodynamics, in case you didn't know."

    "I know," Ymmot said. "I know everything you know. I even know the things that you have forgotten."

    "Like what?" Tommy said.

    "Like what Ms. Trapp taught us in Science," Ymmot said. "Remember what she said about scientists using models? When they want to know how a big thing works they make a little model of it and see how the model works. That's why they put model airplanes into wind tunnels. It lets them figure out how the real airplanes will fly."

    "So if we want to figure out how the real ocean makes waves, we need a model ocean," Tommy said.

    "Yes, we do," Ymmot said. "But we don't have to make a model ocean. We already have one. It's over there in those rocks."

    Tommy went down the stairs to the beach and then ran up the beach to the rocks. The rock he wanted was almost as wide as a house and its almost-flat top was as high above the beach as was the top of his head. He climbed to the top of the rock and found just what he wanted. It was a pool of water a little bigger than a bathtub. He sat down by a part of the pool where the rock sloped under the water like a little beach.

    "Is this supposed to be a model ocean?" he said. "It's too small!"

    "Don't look at how it's different from the real ocean," Ymmot said. "Look at how it's the same. Do you remember from Geography what oceans are?"

    "Oceans are big bodies of water that lie in basins," Tommy said. "That's what Ms. Trapp told us. Oh, I see what you mean. This is a little body of water that lies in a basin."

    "Right," Ymmot said. "Now we have a model ocean. How are we going to use it?"

    "Well," Tommy said, "when scientists want to understand something they figure out all the different ways it could work and then they figure out which of those ways it actually does work. That means that we have to think up all the different ways to make waves and then we have to figure out which way the ocean really uses to make waves."

    "Right," Ymmot said. "And we will use the model ocean to test the different ideas you think up."

    Tommy thought for a moment. Then he put his hand out over the water and smacked the top of the water with a finger. Ripples ran away from where he hit the water, making circles that grew wider and wider until they hit the sides of the pool. Tommy saw that the ripples made little waves when they hit the side of the pool next to him. He looked out at the ocean and saw that the long hills of water that he had seen before breakfast now looked like giant ripples.

    "But there are no giants smacking the ocean with their fingers," he told Ymmot.

    "Right," Ymmot said, "so that idea was wrong. Think up another one."

    Tommy thought some more. Then he picked up a pebble and dropped it into the water. He saw ripples run away from the place where the pebble hit the water.

    "But nobody is dropping giant rocks into the ocean," Tommy said.

    "OK," Ymmot said, "so that idea was wrong. Think up another one."

    "Maybe if I could shake the model...," Tommy half said.

    "You would need an earthquake to do that," Ymmot told him.

    "Yeah," Tommy said. "Hey, I'll bet earthquakes make waves."

    "I'll bet you're right," Ymmot said. "We can look it up in the encyclopedia when we get home. But earthquakes aren't happening all the time."

    "And waves are happening all the time," Tommy replied. "That means I have to think up another idea."

    He closed his eyes and tried to remember all the things he had ever done to water. After a few minutes he got an idea. He leaned close to the water in the pool and blew on it. Ripples ran away from where his breath hit the water.

    "But," he said, "there aren't any giants blowing on the ocean."

    "Maybe it doesn't need giants," Ymmot said. "Do you remember what made old-fashioned ships go? You know, ships like the ones Columbus used."

    "They had sails," Tommy said. "Oh, the wind!" he exclaimed as a new idea came to him. "The wind blows on the ocean all the time. That's why boats can use sails. So it's the wind that makes waves. The wind makes waves for the ocean."

    He stood up and looked out over the ocean, watching the waves come in to crash on the beach. He felt happy inside now, happy like the way he felt on Christmas morning. "I know how the ocean makes waves," he yelled out loud. "I know something about hydrodynamics and I figured it out all by myself."

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