Tear a paper towel into a square that measures about 5 inches by 5 inches. Put 1 1/2 tablespoons of baking soda in the center of the square, then fold the sides of the square in toward the middle, and then the opposite sides in toward the middle, with the baking soda inside. This is your "time-release packet."
Pour into your plastic bag, 1/2 cup of vinegar and 1/4 cup of warm water.
Now here's the tricky part. You need to drop the time-release packet into the vinegar and zip the bag closed before the fizzing gets out of control. You can zip the bag halfway closed, then stuff the packet in and zip the bag closed the rest of the way in a hurry, or you can put the time-release packet into the mouth of the bag and hold it up out of the vinegar by pinching the sides of the bag. Zip the bag closed and then let the packet drop into the vinegar. One way or another, get the packet in the vinegar and zip the bag closed.
Shake the bag a little, put it in the sink or on the ground, and stand back! The bag will puff up dramatically and then give a satisfying pop sound.
Be prepared to do this several times.
The boys suggested that they were like time-released bombs and are thinking of a way of including it in a party with a spy theme.Pin It
UPDATE: Fizzy Explosion Bags was featured at The Boy's Store Blog.