up

Up is like when you look at the sky and see the clouds floating high above your head. Imagine a balloon filled with air, rising towards the sky. That’s what up means; it’s going away from the ground, reaching towards the blue sky where the sun and stars live. Up is the opposite of down, like when you climb a ladder to reach the top shelf where cookies are kept.
Think of a tree. The trunk stands tall, and the branches reach up towards the sun, stretching to catch the sunlight. When you jump, you are trying to go up, just like a bird flying into the air, flapping its wings to soar higher and higher. Up is the direction you go when you want to reach something high, like when you stand on your toes to grab a toy from a tall shelf.
Imagine a rocket blasting off into space, zooming up into the sky, leaving the earth behind. Up is the way it travels, moving further from the ground, exploring the vast space above us. When you throw a ball in the air, it goes up before coming back down.