This weeks video is all about “seeing is believing”! The video is from a series of training videos made back in 1947 for the US War Department to training workers in the factories making war products. These videos may be old, but they are timeless as the chemistry of flammable liquids and gases have NOT changed! This video is one of my favorites as they use special back lighting to show us how the vapor of gasoline (heavier than air) behaves.