Limewater

Limewater is a special drink made by mixing a powder called calcium hydroxide with water. This makes the water look very clear, but also makes it taste very bitter and can make your tummy upset if you drink too much of it.

When doctors use limewater, they may mix it with a little bit of an acid called hydrochloric acid. When these two things mix, they make a special fizzing and bubbling reaction that can tell the doctors if there is something wrong with the patient's digestive system.

Limewater is also used by scientists to tell if something is acidic or basic. If they put a drop of limewater into a liquid and it turns cloudy, then it means that the liquid is acidic. If it doesn't turn cloudy, then it means the liquid is basic.