My sister and I both remember a live-action television show that aired in the US sometime around 2003. It consisted of 3-5 preteens or teenagers at a boarding school. My sister thinks they were in Britain, but I don't agree.
What we do agree on was a supernatural aspect. This was more science-based than magic. I don't remember ghosts or vampires, but maybe robots or shrinking people- things like that.
As for the cast, we're both pretty sure there was a male science teacher who was a good guy. I remember a female teacher being an antagonist, but my sister thinks she was more of an annoyance than a bad guy (she compared her to Filch in Harry Potter). We agree that there was definitely a redheaded girl, and possibly a black girl (but she might have been a later addition). There were two or three boys. One was very smart and kind of a geek. The other(s)- one might have been kind of slow on the uptake? The other was rich, I think. They might have been the same person.
Its maddening that we both remember watching this show, but neither of us knows what its called. Any ideas?