NSES Content Standard D 
Earth and Space Science: Earth in the Solar System
Grades 5-8, page 160

The Earth is the third planet from the sun in a system that includes the moon, the sun, eight other planets and their moons, and smaller objects, such as asteroids and comets. The sun, an average star, is the central and largest body in the solar system.
 

 
Benchmark 4A The Physical Setting: The Universe
Grades 3-5, page 63
The earth is one of several planets that orbit the sun, and the moon orbits around the earth.

Benchmark 4A The Physical Setting: The Universe
Grades 6-8, page 64
Nine planets of very different size, composition, and surface features move around the sun in nearly circular orbits. Some planets have a great variety of moons and even flat rings of rock and ice particles orbiting around them. Some of these planets and moons show evidence of geologic activity. The earth is orbited by one moon, many artificial satellites, and debris.

Benchmark 4A The Physical Setting: The Universe
Grades 6-8, page 64
Large numbers of chunks of rock orbit the sun. Some of those that the earth meets in its yearly orbit around the sun glow and disintegrate from friction as they plunge through the atmosphere--and sometimes impact the ground. Other chunks of rocks mixed with ice have long, off-center orbits that carry them close to the sun, where the sun's radiation (of light and particles) boils off frozen material from their surfaces and pushes it into a long, illuminated tail.

Benchmark 4B The Physical Setting: The Earth
Grades 6-8, page 68
We live on a relatively small planet, the third from the sun in the only system of planets definitely known to exist (although other, similar systems may be discovered in the universe).