The media project for ILT was due yesterday, so naturally I’m posting it today instead. I blame the delay on ambient noise makers of the four-legged variety. (If I ever had a production company I would call it “Can we play now?” and the logo would be a tennis ball.) My media project is a screencast about radiometric dating. I used an analogy that has worked well for me in the past—eating cookies. The cookie-eating analogy lets me explain the main idea behind radiometric dating in an intuitive way, and it also allows me to address a common misconception about the meaning of the term “half-life.”
This process is new to me, and I found it to be relatively painless, other than having to listen to my own voice over and over again. I was happy to have iMovie to splice and dice QuickTime recordings to remove misspeaking, and to take out some of the more obvious pops, breaths, and thumps. The biggest problem I experienced was underestimating the extent of image degradation upon sharing the video to YouTube. Even with the highest quality setting, the text of my image credits is difficult to see. Some of the images that I didn’t create myself are historical and have been in the public domain for a very long time. However, three of the images aren’t historical, and they are important to credit. To avoid re-recording the screencast in its entirety, I added image credits to the end.
The philosophy behind the design of my screencast is based on the idea that learning is a cumulative process. If you don’t have a good foundation, you don’t really have anything. My video is quite basic. I avoided the radiometric decay equation, and the definition of the term “isotope.” In an example, I used the elements uranium and lead because they are elements most people have heard of before (unlike samarium, neodymium, rubidium, or strontium). Carbon-14 would otherwise be a natural choice because people tend to be familiar with carbon-14 dating, but it doesn’t work for the example, or for rocks in general.
There are many resources online to handle the more complex details of radiometric dating. My goal was to establish the essential underlying ideas, and to convince students that radiometric dating is something they can understand. If that is accomplished, the fear factor is reduced, and it is much easier to stuff information into brains.