Help make Alexa smarter on Alexa Answers. Sign in with Amazon


What color are human veins?

Blood is always red. Veins look blue because light has to penetrate the skin to illuminate them, blue and red light (being of different wavelengths) penetrate with different degrees of success. What makes it back to your eye is the blue light, thus making it appear that veins are blue.

{{ relativeTimeResolver(1573494383594) }}

Points points 71

Similar Questions
Sign in to view all similar questions
Science 1 Answer

Join Alexa Answers

Help make Alexa smarter and share your knowledge with the world