New Delhi: We have all seen veins emerging on our wrist or hand. But this is a common look that creates a big question. When we all know that the blood flowing in our body is dark red, then why do we see these veins blue or green? Does blood color change inside the veins? Let us understand the interesting scientific reason hidden behind it.

Is oxygen -free blood blue? This is a myth

Many people have a common belief that the blood color is blue and when it reaches the lungs and becomes oxygenated, it turns red. But it is not true. According to science, blood in our body is always red. Oxygen -rich blood is red in red, while oxygen -free blood is slightly dark red, but it is never blue.

Then what is the secret of blue veins?

The entire game of blue or green looking of the veins depends on the light, our skin and the perception of our brain. To understand this, we have to understand the behavior of light.

• Light game: Sunlight is made up of seven colors (purple, blue, sky, green, yellow, orange, and red). When this light falls on our skin, different colors behave differently with the skin.

• Skin filter: Our skin layers act like a filter. The wavelength (wavelength) of red light is long, so it moves deep in the skin and the hemoglobin present in our veins takes it.

• Blue reflection: At the same time, the wavelength of blue light is small. It is not able to go into the skin too much and after hitting the layers under our skin, it becomes reflected back towards our eyes.

Since only blue light is reflected and reach our eyes, while red lights absorb the veins, so our brain sees it as blue. The deeper the veins are, the more blue appears.

In short, your veins or the blood inside them are not blue. It is just a wonderful game of light and the deception of our eyes, due to which the veins of red blood see blue.