Four open-mouthed glass bottles, labeled A, B, C, and D, are arranged in a stra

Four open-mouthed glass bottles, labeled A, B, C, and D, are arranged in a straight line.All the bottles has distinctly varying amounts of water.They are filled with clear, colorless water. A wooden spoon is being hit against the stem of each bottle, producing sound waves of different frequencies. The lighting is bright and refreshing, with shades of blue and green. The background is a neutral color, such as white or gray. The water inside the bottles must not slosh.