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Use your scissors to cut the bottom off of your cup. I then put a strip of tape around that bottom as it was a but jagged and I did not want to risk my son getting hurt or the balloon getting ripped.
Stretch your balloon a few times and then tie up the end. You are not going to be blowing the balloon up. Once you have tied it off, cut the balloon about two inches below your knot. You are only keeping the knotted end.
Stretch the knotted end over the bottom of your cup, covering the tape. Now use your rubber band around stretch it around the balloon edges to keep it on the cup.
To use the popper you will put a marshmallow inside the cup and then pull down on the balloon knot.
Once you get accurate with your marshmallow popper, make some targets on the ground and make a game out of it. We used rope to lay out circles and assigned a point value to each circle.