In a medium bowl, add half pint of vanilla ice cream (reserve a little bit for the mold if you want to get bites of ice cream). Add root beer to the bowl and fold to combine ice cream with root beer. No need to break the ice cream up, its ok and better if there are still chunks of ice cream.
Pour mixture into popsicle molds filling them halfway. If you reserved extra ice cream, spoon in small chunks and follow with remaining half of mixture.
Cover popsicle mold with foil and puncture hole to allow for wooden popsicle sticks. Place in freezer for at least 2 hours or until set. To unmold, dip mold in a bowl of warm water, or run warm water under bottom of mold.