A bass drum pedal includes a spool-like hub carrying a beater stem; a foot actuated foot board that is pivotally mounted; and a flexible connector directly interconnecting the foot board and the hub. An automobile having a door with a door handle, a drive rod, a latching system, a striker, and a drive rod deformation member. As a result, the inside of the droplets can be observed with a microscope, and results of the reaction of the droplets against other droplets can be measured and classified by stopping and moving the droplets in any direction.