Why do traffic lights have 3 colors of red - yellow - blue and toilet paper must be white?

White toilet paper, traffic lights come in three colors (blue, red, yellow), stripes and stripes . The following article will help you understand why these familiar things have special colors. own.

1. Traffic lights

We are all familiar with the 3 colors red - yellow orange - green of the traffic lights and the meaning of these 3 colors. But why these 3 colors and not the other colors?

All have its causes. 3 colors red - yellow orange - green are the colors with the longest wavelength in the visible light spectrum, so people can see clearly from a distance away both day and night.

2. Commercial aircraft are always painted white

Currently, most commercial aircraft are coated with white paint, and this paint also makes sense. Specifically, please see in the article 'Why do people often choose white to paint aircraft rather than other colors?'.

3. Fire hydrant

Many of us often default to a red pillar. However, in fact, the fire hydrant usually has 4 colors: red, orange, green, blue and each color has its own meaning.

In the US, the color of a fire hydrant depends on its ability to spray water, in gallons of water per minute (GPM), 1 gallon = 3.79 liters.

Specifically, blue is above 1500GPM, green is 1000 - 1500GPM, orange is 500 - 1000GPM, and red is 500GPM.

4. The crosswalk is plaid

The pedestrian crossing of the street is marked by stripes and the black of the road surface creating a contrast that makes them more visible from a distance. This helps drivers easily recognize, thereby reducing vehicle speed. In addition, black and white stripes will help pedestrians crossing the road become more prominent.

5. Characteristic pattern of soccer ball

You may not know, the first ball in football when switching to plastic is only white. Then, to make the ball stand out even more when recording on TV, at that time the TV was only black and white, so adidas sportswear company decided to add black dots.

6. Tires are always black

You may not know, the rubber to make tires really is white. So why are tires black, for details see 'Why are car and motorbike tires black, not other colors?' okay.

7. Toilet paper is always white

When first made, toilet paper is ivory brown rather than white. After that, people bleach the toilet paper to make it most effective. Manufacturers can add color to paper to make products more diverse, but so will cost more, so they do not.

In addition, white also gives users a sense of security.

8. Social network icons - blue

Many major social networks in the world choose blue as the main color on their own logos such as Facebook, Twitter, Linkedin . The reason is because blue makes it safe and reliable, which is why Social networking company wants to give users.

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