Science project due tomorrow :/?

okay i have done NOOO work for this an i'm in serious trouble of maybe getting expelled if i don't finish this i'm in year 8 and i need some ideas for a easy experiment please please help i know i should of done it like 2 weeks ago but i can not go back in time so if that i all you have to say dont i am really looking for some maybe links also something i thought would be just epic if you could explain that whole thing about getting dirty water and cleaning it people said stuff about salt but thats not what i'm looking for. please help its 2:am im desperate