Cosmology and astronomy
Life on Earth and in the Universe

Measuring age on Earth

  1. Chronometric Revolution
  2. Carbon 14 Dating 1
  3. Carbon 14 Dating 2
  4. Potassium-Argon (K-Ar) Dating
  5. K-Ar Dating Calculation

Chronometric Revolution Discussion of the relatively recent changes in our ability as a species to shine light on our deep past

Back

Chronometric Revolution

⇐ Use this menu to view and help create subtitles for this video in many different languages. You'll probably want to hide YouTube's captions if using these subtitles.

Discuss the site

For general discussions about Khan Academy, visit our Reddit discussion page.


Flag inappropriate posts

Here are posts to avoid making. If you do encounter them, flag them for attention from our Guardians.

abuse
  • disrespectful or offensive
  • an advertisement
not helpful
  • low quality
  • not about the video topic
  • soliciting votes or seeking badges
  • a homework question
  • a duplicate answer
  • repeatedly making the same post
wrong category
  • a tip or feedback in Questions
  • a question in Tips & Feedback
  • an answer that should be its own question
about the site