Whether you like it or not, electricity can be very dangerous if not handled properly. It is also scientifically proven that children and electrical outlets are like 2 magnetics and attract to each other (ok its not scientifically proven, it is a fact).
Child Proofing Your Outlets
Electrical outlet caps
I only recommend these for a short time period until you have the outlets replaced to Tamper resistant grade.
Tamper resistant receptacles are a special type of electrical outlet. They are now a common code and required in all homes and most commercial buildings. These outlets are ideal around kids. These outlets replace the old plug in safety covers you can pick up at the dollar store and give you a permanent safety option. They have spring loaded shutters covering the live pins inside the outlet. These covers automatically open up when the ground pin is inserted into the receptacle. Giving you peace of mind, your child will be safe.