* Earth's Gravity: The Earth's gravity is much stronger than the Sun's gravity at the Earth's surface. We are held firmly to the Earth by its gravitational pull.
* Orbit: Earth is constantly falling towards the Sun, but it's also moving forward at a high speed. This combination of falling and moving forward results in a curved path - an orbit. Imagine throwing a ball. It falls towards the Earth, but its forward motion keeps it from hitting the ground directly. Earth's orbit is like a giant, continuous throw around the Sun.
* Distance: While the Sun's gravity is strong, it weakens significantly with distance. The Earth is far enough away from the Sun that its gravitational pull is not strong enough to pull us off the Earth.
Think of it this way: Imagine you're standing on a spinning merry-go-round. Even though the center of the merry-go-round is pulling you towards it, you're still held in place by the spinning motion. Similarly, Earth's orbit keeps it from falling into the Sun, even though the Sun's gravity is pulling it.
