Monitoring internet activity

Its come to my attention that my daughter is using loads of bandwith and i have the suspicion that shes using webcam activity during the early hours. She has a macbook in her room and wireless connection to my router. im fairly confident that shes in some chat/web rooms, and im concerned that she may be doing some unsavoury things and its my internet account - that's all i'll say. How can i check her interent activity to make sure. I know she uses Google Chrome and uses Proxi servers for her surfing as she has already told me in conversation. the thing is she uses the interent for her education research so I'm loathed to just block everything. But if i have the evidence I can educate her.