My oldest son said something very racist and hurtful to me a few minutes ago. I'm not sure how to handle it.

My family is mixed black and asian. Wife is Korean and Japanese. Just so you know the ethnicities involved.This morning my 11 year old got his younger brothers together and broke open a light bulb to "do an experiment".My 7 year old ended up with a cut finger.I was chastising them and asked my 11 year old "why on earth would you think this was a good idea."Then his brother chimed in and whispered "yeah, why did you think it was a good idea?"Then my oldest said "dad doesn't get it. He's all the way black so he's not as smart."I was stunned. That hurt more than I'd like to admit.I sent him to his room.How should I handle this? His mother is at work and isn't answering. via /r/Parenting http://ift.tt/2qQomhG