Coulter counter

A coulter counter is a special machine that can help us count tiny things like blood cells or bacteria.

Imagine you have a big bowl of marbles of different sizes and colors. If you poured all of them out on the table, it would be hard to count them one by one. But if you had a special tool that could put them through a small hole and count how many went through, that would be much easier!

That's kind of how a coulter counter works. You put your sample of blood or bacteria in a special liquid and then run it through a tiny tube with a small hole. As the tiny things go through the hole, they disturb an electric current, and the coulter counter can detect how many things there are and how big they are.

So, instead of having to look at each tiny blood cell or bacteria under a microscope and count them all, scientists can use a coulter counter to do it much faster and more accurately!