My friend needs to stop talking!?

I love my friend and she is one of my best friends but recently all she keeps talking about is school, homework, grades, science, etc. I'm not saying it's a bad thing to talk about from time to time and I know caring about school is great but she overdoes it. She acts more like the teacher now instead of the friend. All she will talk about is science, never about anything else. It really gets on my nerves and on our other's friends! How do I get her back to normal?