Once upon a time, there was a little girl named Nikki who loved balloons. She liked to play with them and watch them float in the air. She wondered why they could fly so high, while she had to stay on the ground.
One day, she asked her father, “Papa, why do balloons float?”
Her father smiled and said, “Balloons float because they are filled with a gas that is lighter than air. Air is made of tiny particles that have weight. The gas inside the balloon has less weight than the same amount of air outside the balloon. So the balloon pushes the air down and the air pushes the balloon up. That’s why it floats.”
Nikki thought for a moment and said, “But Papa, what if I fill the balloon with water? Will it still float?”
Her father said, “No, it won’t. Water is heavier than air, so the balloon will sink. Do you want to try it?” Nikki nodded eagerly and ran to the kitchen.
Nikki filled a balloon with water from the tap and tied a knot. Then she let go of the balloon and watched it fall to the floor with a splash.
She said, “Wow, Papa, you were right! The water balloon is heavy and it doesn’t float.” Her father said, “Yes, dear. And do you know what else floats and sinks?” Nikki shook her head and said, “No, what else?”
Her father said, “Well, anything that is lighter than water will float on water, and anything that is heavier than water will sink in water. For example, a cork floats on water because it has less weight than the same amount of water. A stone sinks in water because it has more weight than the same amount of water.” Nikki said, “Oh, I see. So floating and sinking depend on how heavy something is compared to what it is in.” Her father said, “Exactly. And that’s called buoyancy.Buoyancy is the force that makes things float or sink in a fluid like air or water.”
Nikki said, “Buoyancy. That’s a big word. But I think I understand it now. Thank you, Papa.”
Her father hugged her and said, “You’re welcome, my smart girl. Now let’s go outside and play with some balloons. “
Short stories for kids 