text: A teacher can read the childs face to see if they can help then when they are sad and dont tell anyone, but I also think that it would be an invasion of the childs space, because sometimes when kids or even adults get mad or sad and they dont say anything to anyone it's because they dont want people to know. It could help in somecases like when a child is being bulllied at school and they dont tell someone then the teacher could use the device to see that the child is either sad or mad or even both.