I'm an ecologist, and this is the first thing I learned. You have to "sample" a population. If not, it is going to take you forever! The US census is one of the few processes where we try and count everyone. Most of the time we take subsamples and estimate. We do it during elections and for estimating popularities of TV shows. Ecologists also do it. In this piece I tried to show a few types that ecologists often use. In particular, I followed around a bunch of ecologists that are sampling deer populations. It's pretty fun work, and it's definitely easier than counting every deer in the woods!
A new science video podcast that explains science topics in a fun and exciting way. Great for science teachers to download and show in the classroom. Most videos come with lesson plans or accompanying informational web pages. All hosts and filmmakers are also trained biologists.