Ineed science fair ideas for 4th grade, but i need something that won't need a oven, sunlight, etc. also, i need something that isn't common (example: volcano) but still simple!

Something simple?
Hmm, how about a diagram of a fod chain? Its simple, if you dont have a printer to print the images of a food chain, or animals, then just try to draw it the best you can...
Make it into a poster, write some information about the animals, who eats who, are they a carnivor, herbivor, you know... Stuff like that :)
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Hope this helped! :)

Neptune is the eighth planet from the sun. it was the first planet to get its existence predicted by  mathematical calculations  before it was actually seen through a telescope on sept. 23, 1846. irregularities in the orbit of  uranus  led french astronomer alexis bouvard to suggest that the gravitational pull from another celestial body might be responsible. german astronomer johann galle then relied on subsequent calculations to   spot neptune via telescope. previously, astronomer galileo galilei sketched the planet, but he mistook it for a star due to its slow motion. in accordance with all the other planets seen in the sky, this new world was given a name from greek and roman mythology — neptune, the roman god of the sea.