In extreme rage she will throw things, but she has never gotten violent. She yells at me about everything. As of now she is a great mom, but I'm concerned when he gets older, she will exhibit these same behaviors to him.
She will most likely treat your son in a similar manner. You are seeing how she handles people she thinks she has power over. The person she has the most power over is your son.
My ex did this with our son. When my son was old enough to talk, he used to beg me to not leave him with his father even when I went shopping. I asked him why. He said because when I was not around, his father treated him the same way his father threated me. That was a scary thing to hear. So I made sure that my son was not alone with his father.
Does she work full time? Or is she home alone with your son a lot?
Who does most of the taking care of your child when the two of you are home together?
This is even more of a reason to get the spy cameras in your home. See how she treats him when you are not there.
If she is throwing things she is being violent. This is the first level of domestic violence. If you can get her throwing things on video, you can file domestic violence charges against her.
Does she mostly throw your stuff around when she does this?
When she is yelling, etc, do you ever leave the room she is in? If so, what does she do if you try to leave the room and get away from her?
What do you do when she is yelling at you (and maybe throwing things)? Do you argue back? Do you yell back? Do you try to explain yourself?