For the first one we took 1 tsp of baking soda and 1oz of water and dissolved it in the bottom of an empty water bottle. Then he poured in the 2 oz of vinegar and I QUICKLY slipped the balloon over the top of the bottle. And...tada the balloon inflated. (because of carbon dioxide you create)
The next project was called Magic Colors. This took some time. He painted the front of two circles blue and the back of one yellow and the back of the other red. (I held them when he painted the backs.) Then we hung them up to dry and then we waited and waited and waited...When they were mostly dry I poked holes (two on each side) and threaded some string through them. Then you are supposed to twirl it a around and then release it and your eyes are supposed to see the color purple for the red/blue one and green for the yellow/blue one. At first it didn't work because our circles were too big. So we cut down the circles and tada! It worked! Make sure to look right at the circle.