Tom is studying about the Moon in science class. Teacher shows a picture about the surface of the Moon is covered with dust and then teacher puts the planet machine on the table. When she turns on the machine, the moon casts a shadow on Earth, because the Moon is between Earth and the Sun. Teacher explains"It is solar eclipse." It is amazing. So, he decides to observe uncommon special event when a solar eclipse occurs. sembra naturale?

This is how I would rewrite it, and I'll explain after some comments on why I made those corrections. "Tom is studying about the Moon in science class. His teacher shows a picture of the surface of the Moon, which is covered with dust, and then the teacher puts a planet machine on the table. When she turns on the machine, the moon casts a shadow on the Earth because the Moon is between the Earth and the Sun. The teacher explains, "It is a solar eclipse." It is amazing. So he decides to observe uncommon events that happen when a solar eclipse occurs."

First, be careful about missing "the" or "a," or which you should use. When you talk about a "planet machine," this is not common knowledge for most people and so when introducing it for the first time, you should use "a," and afterwards now that everyone has read about it, you can use "the." Also try to remember that you should use "a picture of ~" as a set phrase. "A story about ~" is fine, but "a picture about ~" sounds unnatural. The last thing is where you wrote "uncommon special events," which I guess is okay, but to me sounds a little strange, as something "special" tends to be implied as uncommon. So I would just say "uncommon events." I hope that helps! If you have any questions, let me know!