Across
- 5. After three half lives, you expect this percent of a radioactive substance to remain.
- 6. The process in which an element releases radiation to become stable.
- 10. The Earth is approximately __ years old.
- 12. The half live of C-14 in years.
- 13. After one half of a half life, you expect this percent of a radioactive substance to remain.
- 14. Radiation that releases helium atoms.
- 17. The guy who was the first to determine the age of the Earth.
- 19. The idea that a process you can observe likely happens elsewhere in the same way.
- 22. The naturally preserved remains of living organisms.
- 23. Radiation that causes a radioactive element to lose 4 amu.
- 24. Radiation that releases electrons.
- 25. After one half life, you expect this percent of a radioactive substance to remain.
- 26. The time it takes 50% of a material to decay.
- 27. The most dangerous type of radiation.
- 28. The idea that sediments are originally formed in flat layers.
Down
- 1. After five half lives, you expect this percent of a radioactive substance to remain.
- 2. The half life of U-238 in years.
- 3. Any time the rock layers are messed up from the rock cycle, erosion, etc.
- 4. __ __ is used to determine the age of many animal remains.
- 7. Different versions of the same element are called __.
- 8. After four half lives, you expect this percent of a radioactive substance to remain.
- 9. After two half lives, you expect this percent of a radioactive substance to remain.
- 11. Patterson used the decay rate of __ to determine the age of the Earth.
- 15. Patterns of rock formed by intrusions.
- 16. Radiation that releases light.
- 18. The decimal on the atomic mass of most elements comes from the __ of all known isotopes.
- 20. Determining the age of something by comparing it to its surroundings.
- 21. Chunks of older rock broken off in younger rock.