It's that age when they're trying to be independent but don't have the abilities they need so get frustrated easily. You and they are fine/normal; you can live through this.

http://www.mamashealth.com/child/temper.asp

http://www.kidsgrowth.com/resources/...il.cfm?id=1885

http://en.allexperts.com/q/Parenting...old-temper.htm