Do you know why different colored strips of toothpaste don't mix?

Sometimes in the morning thoughts come into my head that have nothing to do with everyday affairs. For example, why don't multi-colored strips of toothpaste mix in a tube? And why were they needed at all? Let's try to answer both questions.

Some believe that the stripes of paste are of different colors. divided in a tube in several containers and is combined only when squeezing. But to make sure that this is not so is quite simple: if you take and cut the tube right now, then you will not find any special departments there.

Video snippet: Play with me - Toys for Kids / YouTube

Generally, when toothpaste just came up with, the coloring material was really stored in the compartments at the neck of the tube. This trick invented Leonard Marrafino in 1955, and his design is still in use today. The diagram below shows how such a tube works.

In 1990, Colgate-Palmolive patented a similar design, but with more dye compartments to allow different shades of streaks in the paste.

And later, in 2016, the company simplified design to save materials. Now there are no containers with dyes in tubes - the paste is stored in one container. Multi-colored stripes are already added to the bulk. They don't mix because have different viscosity.

Video snippet: CNN/YouTube

Great, you say. But why such difficulties? What are the strips in the paste for, from a practical point of view?

Yes, for nothing. different shades added for marketing purposes so that people buy pasta that looks more interesting. Sometimes colored strips may include additional active substances, but this is very rare. Basically, they are just needed for beauty.