There is a common misconception that blood, as it courses through our veins on its return trip back to the heart, is blue. When you look at your arms you see blue veins, but this is a trick of light, or rather a problem with wavelengths. According to Live Science , light has to penetrate your skin in

order for you to actually see your veins, and blue light waves are more successful at this process, making your veins appear blue. So what does happen to your blood as it moves about your body? Learn the details by reading more.

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Body Knowledge: Red Blood, Blue Veins?