Norah had candy in that cup she is holding, an M&M for every word she spelled correctly when we practiced her spelling list. Avril was going straight for the candy... thus the hand in the face. (Note: I didn't think the scene would get so ugly so fast or else I wouldn't have been taking pictures when I should have been preventing an incident.)
Right now, Avril's not being home schooled in any official capacity like Norah is, but Avril's definitely a student in "the school of hard knocks." Lately, she will do things that really test her sister's self-restraint such as sending Norah's delicate Lego creations to the ground with one swoop of her little arm, expecting Norah to do nothing but smile with her because the Legos made a really cool sound as they crashed all over the wood floor...
After this, Avril seems totally surprised to find herself flat on the floor along with the Legos, staring up at the ceiling. But, Norah doesn't seem surprised in the least to find Mommy standing in the doorway with that look on her face... again.