Freediving with balloons (Weird Science Experiment 4)

http://www.youtube.com/subscription_c... Freediving with balloons -- observing the way balloons react to different pressure environments A balloon is inflated at the surface and swum down to 30 ft+ below sea level. We see that the balloon shrinks as is goes deeper. We then attempt to pop the balloon underwater with a knife, but that proves difficult when the balloon is under pressure. Then we swim down to 60 feet where we find a stingray--not affiliated with our experiment team :-) Here we inflate the second balloon with compressed air. This balloon expands drastically as we swim it back to the surface. In addition to demonstrating the effects of pressure on size, this experiment is a good demonstration of light absorption underwater (water absorbs different wavelengths of light at different rates, red goes first). The balloon is red, but at the bottom it looks blue-grey. As we resurface, it goes from blue-grey back to brilliant red through shades of purple.