Then go sit by her and talk. Being on the opposite side of the room won't build a relationship right?
There is a shy girl in my science class and I want to become friends I'm in 8th grade and we sit across the room?
She will break your heart I did with the girl who I fell in love with she's with someone
Maybe after school if you see her by her locker ask her a question about homework. If you're both confused you can help each other out, that way you become friends or even more than friends who knows!
Make eye contact and smile, but not too often, when in class. If you see her outside, saying hi will do
I think it's great that you want to become friends with a shy girl in your science class. She probably wants to be friends too!
Have you noticed if she has a cool bag, or pencil case or maybe an item of clothing? You could introduce yourself on the way out of class and compliment her.
Or... The plain and simple approach
You could just go up to her next time you see her around, and just say "Hey! I'm ____. I've seen you in my science class. How are you finding things?" and she might just engage in conversation with you right there and then. Many shy people are okay once someone makes the first move! Good luck.
How NOT to make friends...
I found this video by MisterEpicMann and they're always quite funny. Maybe don't do these things if you want to be friends with this girl...