Lesson Plan - Get It!
As you walk through a museum display of natural history, you stop to read a sign below a dinosaur bone. The sign suggests the dinosaur bone is from the Jurassic Period and is approximately 200 million years old. Then you start to wonder, "Who figured out how old the bone is, and how did they determine its age?"
The scientists that studied and dated the bone — paleontologists — used some advanced form of scientific dating.
- Did they use radioactive dating?
Start by acquiring a basic understanding of what radioactive dating is; otherwise this lesson doesn't have much value.
Before doing so; if you missed or need to review the first Related Lesson in our Mysteries of Geology series on how trees can be used to date objects, you can find it in the right-hand sidebar.
Radioactive dating is one method used by scientists across many fields to date objects, including bone, rock formations, and soil samples — essentially anything for which the age is unknown. There is more than one type of radioactive dating, but all types of radioactive dating work on the premise that radioactive isotopes decay at a measurable rate.
Carbon-14 dating is one of the best-known radioactive dating methods, and it is the one that you will explore in the first part of this lesson.
Carbon-14 dating is used by scientists to estimate the age of once-living things, usually referred to as fossils. Here is a quick overview from Mocomi of what it is and how the method is applied: Carbon Dating.
As you read this, you are probably thinking it sounds logical and pretty simple, but as with all things in nature, it is rare to have any situation where all of the circumstances are aligned to give perfect information, so scientists have to work using some assumptions.
This is where scientists begin to disagree about the accuracy of dates established using this method. Watch this super video that explains how scientists use the half-life of Carbon-14 to date objects, but listen carefully to How Carbon Dating Works (Brain Stuff), and you should catch on to a few reasons why its accuracy can be questioned, both now and even more so in the future:
Move on to the Got It? section to examine some necessary assumptions.