Little diver Philip sat on the edge of the large white bathtub. For him, it wasn't just a bathtub. It was an endless ocean full of secrets. The foam bubbles were mysterious islands, and the shiny faucet was a waterfall that filled his world with warm, pleasant water.
His owner, a boy named Adam, gave him a gentle push. "Ready for a new adventure, Philip?"
Philip, who was made of sturdy plastic and had a brave smile painted on his face, plunged just below the surface with a cheerful "splash." The water caressed him pleasantly. He felt light and free, as if he were floating among the clouds. He swam just beneath the surface, admiring how the light refracted on the bubbles, and everything seemed peaceful.
"Now let's dive deeper!" Adam announced. He gently pushed on Philip's helmet with his finger, and the little diver began to sink.
As he sank lower and lower, he began to feel something strange. It was no longer just a gentle caress. The water suddenly seemed to be hugging him. At first, it was faint, like someone taking your hand in friendship. But the deeper he went, the tighter and stronger this hug became. When his little plastic feet touched the bottom of the tub, he felt as if the entire immense mass of water wanted to squeeze him in one big, powerful embrace.
"Strange," Philip thought. "Why is it completely different down here? Why is the water squeezing me so tightly?"
Adam pulled him back to the surface, onto a small foam island. Water trickled off Philip in little streams.
"You noticed it, didn't you?" Adam asked. "Did you feel how the water hugged you more and more, the deeper you went?"
In his imagination, Philip nodded.
"Do you know why that happens?" Adam continued. "Imagine the water is like a big, invisible blanket. When you're just below the surface, only a very thin layer of this blanket is lying on you. But when you dive all the way to the bottom, a whole column of water is lying on you. All that water above you has weight, and it pushes down on you with that weight."
Philip tilted his little helmet. A column of water? That sounded interesting.
"Wait, I'll show you," Adam said and disappeared from the bathroom. He returned a moment later with an empty plastic bottle. "With the help of a mom or a dad, we can do a little experiment."
Adam carefully took a pair of scissors and made three small holes in the bottle. One at the very bottom, near the base. A second one in the middle. And a third one at the top, near the neck. Then he covered the holes with clear tape.
"Now watch, Philip, what water pressure is," he said ceremoniously. He filled the bottle with water to the very brim and placed it on the edge of the tub.
"Ready?" Adam quickly ripped off the sticky tape.
And then it happened! A thin stream of water began to spray from each hole. But they didn't all spray the same way! The water from the top hole trickled out lazily and landed a short distance from the bottle. The stream of water from the middle hole was already a bit stronger and reached farther.
But the bottom stream! It shot out of the bottle with immense force, creating a beautiful arc that landed far away in the bathtub ocean.
"Do you see?" Adam exclaimed enthusiastically. "The most water is pressing on the bottom hole—the entire column of water above it. That's why that stream is the strongest. Less water presses on the middle hole, and almost none on the top one. That's exactly what you felt!"
Philip looked at the little fountain, and suddenly it all made sense. That strong hug at the bottom was nothing other than the weight of all the water above him. It was pressure. And he, the little explorer, had just uncovered one of the great secrets of his ocean.
"So, the deeper I dive, the greater the water pressure I'll feel," he said to himself.
"Exactly, my clever explorer!" Adam praised him, as if he had read his mind. "And now that you know this secret, are you ready for another expedition to the bottom?"
Philip smiled his painted smile. But this time, it wasn't just the smile of a brave diver. It was the smile of a diver-scientist who understood the world around him a little bit more. With a cheerful "splash," he dived again. And as he descended, he no longer wondered at the strengthening embrace. Instead, he imagined the huge, invisible column of water above him and felt like a true hero, penetrating the depths of knowledge.
And what about you, kids? Will you try to build a water fountain like this from a bottle with your parents? Observe which stream of water sprays the farthest. Perhaps your toys, too, will have a great adventure and discover the secret of water pressure.