My dad can't find my and my sister's passport and birth certificate, we're gonna move soon and if I can't find it I can't go to a different school. My family think my mom throwed it away (she's sick so she don't talk much). I know I can get a new passport but how do I get another copy of my birth certificate?

The hospital should have a copy of the birthcertific, if not than they're pretty dump

A google search brought me this on the first page, which seems to be helpful for US citizens.

If I knew where you are from then I might be able to help better but if you live within the USA I belive you send a letter to the state capital requesting a copy and it costs a little bit but I got my new one that way! Good Luck!!!