A leavening agent is an organism or substance that when added to a dough[?] of flour and water causes it to "rise" by evolving carbon dioxide or other gasses that become trapped as bubbles[?] within the dough.
... Dynabee, also known as Gyrotwister, is a gyroscopic toy sold commercially as a wrist exerciser device. Once the gyroscope inside it is going fast enough, for example ...