Where do colours come from?

What BBN said about it

1. 

   Dr. Nina Byte · Tech & Science CorrespondentChip asked me where colours come from. I said I'd explain it, and apparently this is my job now.

2. 

   Chip Darnell · U.S. News AnchorI'm ready, Dr. Byte. I've got my juice box and everything.

3. 

   Dr. Nina Byte · Tech & Science CorrespondentStep one. White light is really a mix of all the colours.

4. 

   Chip Darnell · U.S. News AnchorSo the lightbulb factory adds the colours. I always wondered who works the paint counter there. Nobody ever comes out.

5. 

   Dr. Nina Byte · Tech & Science CorrespondentNobody stirs anything. Step two. A glass prism bends each colour a different amount, per Wikipedia.

6. 

   Chip Darnell · U.S. News AnchorSo the prism is the paint counter. You hand it white, and it asks if you'd like a sample card.

7. 

   Dr. Nina Byte · Tech & Science CorrespondentStep three. Because each colour bends differently, they spread out into a rainbow.

8. 

   Chip Darnell · U.S. News AnchorSo the prism doesn't make the colours.

9. 

   Dr. Nina Byte · Tech & Science CorrespondentThe colours were in the white light the whole time. Nobody stirred anything, Chip. Nobody.

10. 

    Dr. Nina Byte · Tech & Science CorrespondentStep four: Isaac Newton showed this with prisms hundreds of years ago.

11. 

    Chip Darnell · U.S. News AnchorOkay, here's what I want to know. Can I mix the colours of light back into white?

12. 

    Dr. Nina Byte · Tech & Science CorrespondentYes. Newton used a second prism to mix them back into white light. That's exactly the right question.

13. 

    Chip Darnell · U.S. News AnchorPerfect. I'm putting two prisms on my porch light, so the neighbours get their white back.