Once upon a time, nestled in a fluffy cloud high above the sparkly, twinkling stars, lived a little round cloud named Nimbus. Nimbus wasn't just any cloud; he was a very curious cloud. He loved to watch the big blue thing that shimmered and shone below – the Earth! But Nimbus had a BIG question: Why is the Earth round?

He'd asked all the other clouds – the wispy ones, the fluffy ones, even the grumpy, rain-making ones. They all shrugged their fluffy shoulders and said things like, "It just is," or "Nobody really knows!" This wasn't good enough for Nimbus! He wanted a real answer.

So, Nimbus decided to take a trip! He zipped down from his cloud home, carefully avoiding the raindrops (he didn’t like getting wet!), and landed softly on a giant, colourful balloon. This wasn’t just any balloon; it was a special, magical balloon that could fly all the way to the Earth and even take him around it!

He bounced gently as the balloon started to drift towards the Earth. As he got closer, he saw amazing things! Vast oceans that shimmered like a thousand sapphire jewels, sprawling green lands dotted with tiny, colourful patches, and towering mountains that poked into the sky like giant fingers.

"Wow!" Nimbus gasped, his little cloud body tingling with excitement. But he still hadn't answered his question.

As the balloon continued its journey, Nimbus noticed something strange. He saw the edge of the land, and instead of it ending abruptly, it seemed to… curve! He tilted his head and peered over the edge. The land continued, curving downward, disappearing into the distance. It wasn't flat at all!

Nimbus giggled. He flew his balloon even closer, and this time he looked down. He saw the curving land continue further and further, until it met back up with itself, forming a perfect circle.

"It's round!" Nimbus exclaimed, his cloud body shaking with glee. He felt like he was floating on a giant ball!

But why? Nimbus still wanted to understand. He had a friend, a wise old star named Stella. Stella was known for her brilliance and her knowledge of the universe. She lived in a faraway galaxy, but Nimbus knew she could help him.

So, Nimbus, on his magical balloon, embarked on another adventure, soaring through the star-dusted sky towards Stella’s galaxy. It was a long and exciting journey, filled with shooting stars and playful comets that zipped past him.

Finally, he reached Stella. Stella, a twinkling ball of light, greeted him warmly. "Nimbus, my little cloud friend! What brings you to these distant shores?" she asked.

Nimbus explained his journey and his discovery. "I've seen that the Earth is round, but I don't understand why it's round," he said, puffing out his little cloud body with concern.

Stella smiled gently. "It's all about gravity, Nimbus," she explained, her voice as soft as starlight. "Gravity is a powerful force that pulls everything towards the center of the Earth. Imagine a big ball of dough – the Earth started as a giant cloud of dust and gas, just like me and you, but much, much bigger. Gravity pulled all that dust and gas together, and as it did so, the pressure in the center became so strong that it squeezed everything into a round shape. It's like squeezing a ball of playdough in your hands, it naturally forms a round shape because gravity pulls it in from all sides."

Stella continued, "Think of a spinning top. When it spins really fast, it stays upright, right? Well, the Earth also spins, and this spinning helps to make it even more round. The force of the spin is constantly pushing outward, balancing the force of gravity pulling inward. This constant balancing keeps the Earth a beautiful, round sphere."

Nimbus listened intently, his little cloud eyes wide with wonder. He understood! The Earth was round because of the amazing power of gravity and the way it pulled everything together, shaping it into a perfect sphere. He also learned that the Earth’s spin helps keep it this way.

Nimbus thanked Stella and zipped back to his home in the clouds, feeling much wiser and happier. He knew he could now answer his big question, not just for himself but for all the other clouds. He flew around his cloud friends, excitedly telling them all about his adventure, and how the Earth is round because of gravity and its spinning. And from that day on, all the clouds knew why the Earth was round, thanks to Nimbus's incredible journey. He even wrote a book about his adventure, called "Nimbus's Round Earth Adventure," and shared it with all the children living on the big, round, beautiful Earth.