Tetrazolium chloride

Tetrazolium chloride is a very special kind of powder that is used to test if something is alive or not. The powder looks like salt or sugar but it is a different kind of chemical.

When you mix tetrazolium chloride with a living thing, like a plant or a bacteria, it turns into a colorful substance that shows that the living thing is alive and well. You see, living things are always using up energy in their bodies to do different activities, like grow or move or even breathe. Tetrazolium chloride is able to detect the energy being used up and it turns into a pretty color when it senses this activity.

But when you mix tetrazolium chloride with something that is not alive, like a rock or a piece of metal, it does not change color. This is because these things don't have any energy being used up in them, so the tetrazolium chloride doesn't react with them.

Scientists use tetrazolium chloride to check if different things are alive or not. They might use it to see if a cell sample in a lab is still functioning, or if a piece of tissue in a patient's body is still healthy. It's a very useful tool to have, especially when trying to understand how living things work!