Why do you think rachel did not speak up and advocate for herself in the book "eleven" by sandra cisneros

She maybe didn't feel confident in herself or the character itself is shy. I'm not sure if I read the same book but Rachel might feel like she was wrong and her teacher was right.

onto a large boat, and mark the water level that the boat sinks to. then, take the elephant out and put a bunch of marked weights onto the boat until it reaches the same water level. add up the masses of the weights to get the weight of the elephant.