A performance was taking place on the surface of a small pond. The sun reflected off the water like a thousand tiny mirrors, and right in the middle of this glow, Clara the water strider was dancing. Her thin, long legs glided across the surface so gracefully, as if she were made of a feather. She moved quickly forward, then made an elegant turn and stopped, as if standing on solid ground.
From the bank, hidden among the blades of tall grass, Ferdie the little frog was watching her. He frowned, puffed up his green cheeks, and muttered under his breath: "That’s not fair." Then he pushed off and with a big splash, jumped into the water. The waves rushed all the way to Clara, who just bobbed gently on them.
"Clara!" croaked Ferdie as he surfaced and shook the water from his eyes. "How is that possible? I get completely submerged, and you run on the water as if it were a meadow!"
Clara approached him with a cheerful smile. "Hello, Ferdie. It’s not magic, but a great secret of the water."
Just then, on a water lily leaf near the bank, Dot the little ladybug stirred. "A secret? I love secrets! What is it?" she asked curiously, rubbing her antennae. Right next to her, Eliza the little snail was slowly inching along, curiously poking out her eyestalks.
"It’s a secret about strength and friendship," said Clara, stopping so close that everyone could get a good look. "Imagine that this whole water surface is made of tiny, invisible water drops. And each of those drops holds hands very, very tightly with its neighbors."
Ferdie scratched his head. "Water has hands? I’ve never heard that before."
"It doesn't have real hands," Clara laughed. "But the tiny drops press against each other so strongly that together, on the surface, they create something like a thin, flexible skin. It's called surface tension. It’s like an invisible film."
"A film?" asked Dot. "Like a spiderweb?"
"A bit like that, but it's made of water," Clara explained. "It’s strong enough to hold me up because I am very light and my weight is spread out over my long legs. But when you, Ferdie, jump into the water, you are heavier and your jump easily breaks that film."
Ferdie still looked doubtful. "So if I were lighter, I wouldn't sink either?"
"Let’s find out!" Clara suggested. "This will be our first experiment. Dot, could you find a dry leaf from a tree? One that is really thin and light."
Dot huffed, spread her little red wings, and a moment later, she returned with a small, yellow birch leaf. She carefully handed it to Ferdie.
"And now," said Clara, "try to place it very slowly and gently on the surface. Don't push it, just let it go from a small height."
Ferdie held his breath. He held the leaf with his tongue and then carefully let it fall onto the water. The leaf touched the surface lightly and... it stayed there! It bobbed on the little waves, but it didn't sink.
"It works!" Ferdie cried out with joy. "The water skin is really holding it!"
"Excellent!" praised Clara. "And now we'll try something more advanced. Eliza, you move slowly and are very patient. Will you please find us one thin, dry pine needle?"
Eliza the snail looked around and after a moment, she found one exactly as Clara had described at the roots of a tree. She slowly brought it to the water's edge.
"The needle is heavier than the leaf," Clara warned. "If we just toss it in, it will surely break the water film and sink. We must be very, very careful."
She took two thin blades of grass and used them to hold the needle flat. "Now, we will place it on the water together. Completely horizontal."
The first attempt failed. One end of the needle touched the water first and immediately sank to the bottom. "Never mind!" Clara said cheerfully. "Now we know how not to do it. We have to place it all at once. Let's try again!"
They found another needle. This time, everyone concentrated. Clara and Ferdie held the blades of grass and slowly, very slowly, lowered the needle to the surface. It touched... and stayed there! It floated on the water like a little boat.
"Yay!" squeaked Dot. "We did it! I can see how the water skin bent just a little bit underneath it, but it didn't break!"
"Exactly," nodded Clara. "And that's precisely what happens under my feet. I spread my weight and stand gently on this amazing, invisible water trampoline."
Ferdie, Dot, and Eliza were thrilled. They spent the whole afternoon playing a new game. They carefully placed flower petals, small feathers a bird had lost, and dry dandelion seeds on the surface. They wrote in the sand on the bank what sank and what stayed afloat. They discovered that even a heavier object could stay up if its weight was well distributed, but even a light little thing would sink to the bottom if they threw it too quickly.
When the sun began to sink towards the horizon, painting the sky orange, Ferdie was smiling from ear to ear. "I learned something amazing today. Water isn't just wet, it's also strong and it sticks together!"
Clara looked at him and winked. "You see? An adventure or a mystery awaits at every turn. You just have to look closely and ask: why?"
And what about you, children? With the help of your parents, try filling a bowl or a deep plate with water at home. Then, very carefully, perhaps using a piece of paper, try to place a small metal paperclip or a thin sewing needle on the surface. Do you think you will succeed in discovering this invisible and strong skin of water?