Exploding Sandwich Bag

Materials: sandwich-sized Ziploc bag, 1/4 cup warm water, 1/2 cup vinegar, 1 tbsp. baking soda, toilet paper 

(It's helpful to have two people working together on this) Tear off a square or two of toilet paper and put a tablespoon of baking soda in the middle.  Twist or fold the toilet paper around the pile of baking soda making a small packet. 

Next, open your sandwich bag and pour in 1/2 cup vinegar and 1/4 cup warm water. Zip the bag closed, but not all the way.  You'll want a small opening just large enough to drop in the packet of baking soda. Move the experiment to the sink or outside!  Put the baking soda packet into the bag and then quickly zip it all the way closed.  (I found it helpful to carefully put the packet in, then hold it towards the top away from the liquid so I could zip the bag all the way closed, then let it drop in) Once the bag is sealed, give it a quick, gentle shake so the packet drops into the liquid and set it down. (Be sure the children are standing back away from bag)  The reaction will occur almost immediately, and the bag will start to fill with carbon dioxide.  It'll get bigger and bigger until it finally POPS!