High-speed recordings of the experiment then allowed them to study its evolution in great detail, including the development of the lubricating layer of air. There is air within a pyroclastic flow.

You can read more about our testing protocol in the How we test section below. Unsure what kind of fitness tracker would work for you? Check the How to choose section for useful advice ...

In fact, even if you are just on the lower side of that 100-250 mg/dL safe exercise range, many experts recommend that PWDs eat a pre-exercise snack of between 15 and 30 carbs to avoid being sent ...

The latest news and headlines from Yahoo News. Get breaking news stories and in-depth coverage with videos and photos.