We've been told and tell are children that warm air rises. But can we really show that is true. This demonstration is easy to do and very dramatic. You will want to do it several times. Take the tea bag and remove the staple from it. Let the tea loose and open up the bag. Do not rip the staple out gently pull it loose. You need the type of tea-bag that forms a tube. Inexpensive variety's tend to be this type. Stand the bag up on a plate or other fire safe surface. You need to open the bag until it forms a circle on the base for it to stand up. It takes some balancing to get this experiment to work. Light the base of the tea bag on fire. Wait the fire will quickly burn the tea-bag. When there isn't much of the tea bag left, it will rise into the air in front of your eyes like a miniature hot air balloon (one that is on fire :) )It will burn itself out in the air and fall back down as harmless ashes.