Synopsis
The Crab Nebula Contrasts and compares the effect of two kinds of dam-building -- that done by beavers, and that done by human engineers. Points out how man is damaging the ecological balance of nature whereas the beaver is not.
Uploader's description on archive.org
Details
- Running time
- 30 minutes
- Language
- English
- Collection
- Educational Films, Ephemeral Films
Subjects on the Internet Archive
- Astronomy
- Solar system