Why does toothpaste have colored stripes but when squeezed out it doesn't mix?

This is an interesting technological secret that combines physical design and chemical formula.

Toothpaste with attractive colored stripes has become a familiar image in daily life. But have you ever wondered why these colored stripes remain the same shape when you squeeze the tube without mixing? This is an interesting technological secret that combines physical design and chemical formula.

The answer starts with how toothpaste is made . A striped tube of toothpaste isn't a random mix of ingredients. Instead, the stripes are carefully arranged in the tube by dividing it into different layers or compartments . The white toothpaste usually takes up most of the space in the tube, while the colored toothpaste is placed in a separate section, usually near the top of the tube. When you squeeze the tube, pressure forces both parts of the toothpaste out through a special nozzle.

The color stripes are carefully arranged in the tube by dividing it into different layers or compartments.

The structure of the nozzle is crucial to keeping the coloured stripes intact. The nozzle is designed so that the coloured cream is only pushed to the surface as the white cream passes through, creating distinct stripes. Interestingly, the coloured cream does not mix with the white cream, as both are highly viscous and made from the same base material (usually a gel or paste). This prevents them from mixing as they move through the nozzle.

Another unique feature is that the cream squeezing process is always controlled by uniform pressure . When you squeeze hard, the cream in the entire tube will move uniformly. This helps the colored cream and white cream come out at the same ratio, ensuring that the stripes always remain sharp even when you use the tube almost empty.

Toothpaste manufacturers also have to fine-tune their formulas so that the colors in their toothpastes do not bleed or fade over time. Colorants are often added in very low concentrations and stabilized with chemical additives to keep the color clear. This not only makes the product look appealing, but also maintains the advertised oral hygiene benefits.

This technology, while simple, is a meticulous process in consumer manufacturing. The next time you squeeze a tube of toothpaste, take a moment to look at those perfectly colored stripes and think about how they were created – a delicate combination of physical design, chemistry and engineering. The familiar things in life sometimes contain secrets that are worth being curious about!