You will need: a piece of yarn or fishing line, approx. 6 feet (2 meters); a balloon; 2 chairs; a cocktail straw; tape; a pair of scissors. Tie the string to the back of a chair. Thread a straw onto the other end of the string, and then tie the string to the back of the second chair. Inflate the balloon but don’t tie the end, and attach it to the straw using tape. Now let your rocket go!