Make your own DIY paper rocket propelled by Alka-Seltzer. First, tape a toilet paper roll to the center of a paper plate. Then, fill a film canister with one tablespoon of water and an Alka-Seltzer tablet. Quickly put the lid on the canister, and drop it lid-side-down into the toilet paper roll. Step away, and count down to blastoff! You can get more creative by decorating the canister, or keep it simple for an easy, kid-pleasing entertainment.