Make a concentrated solution of red cabbage extract by boiling a cup of shredded red cabbage in a cup of water for about 5 minutes. Pour this extract into a large transparent container, such as a vase or a 2-L plastic bottle with the top cut off. Add a tablespoon of white vinegar to acidify the solution. Ask yourself or a classmate what would happen to the pH of this solution if you were to fill the container with plain water. Would the pH go up or down, or stay the same? Test your prediction. As you dilute the solution, the color grows lighter, but what happens to its hue? How can adding plain water change the pH of a solution? Might plain water be used to make this solution alkaline?