Explain why a dust is much more explosive than is a stalk of grain.
Everything you ever wanted to know about dust explosions.
http://en.wikipedia.org/wiki/Dust_explosion
A dust is much more explosive than a stalk of grain due to its fine particle size and increased surface area. When dust particles are suspended in the air, they can form a highly flammable mixture that is easily ignited by a spark or heat source. In contrast, a stalk of grain consists of larger particles, and although it can burn, it is less likely to lead to a rapid and explosive combustion.
To understand why dust is more explosive, let's look at the factors that influence the explosiveness of a material, such as the particle size, concentration, and flammability. Dust particles are extremely small and often in the range of micrometers, making them highly reactive when in contact with an ignition source.
The increased surface area of dust particles allows for more efficient oxygen transfer during combustion, leading to a rapid and intense release of energy. As a result, even a small amount of dust in the air can create a potent explosive mixture. In contrast, a stalk of grain has larger particles, which limits the amount of surface area available for rapid combustion.
Another factor contributing to the explosiveness of dust is its ability to disperse and suspend in the air. This suspension of dust particles creates a homogeneous mixture, increasing the likelihood of an even distribution of fuel that can readily react with an ignition source. On the other hand, a stalk of grain tends to remain localized and does not easily disperse into the air, making it less prone to rapid combustion.
It is essential to note that the combustibility of dust also depends on its chemical composition. Some types of dust, such as those from coal or certain metals, can be highly flammable and explosive even in small concentrations.
To summarize, the fine particle size, increased surface area, and suspension capabilities of dust make it much more explosive compared to a stalk of grain. Understanding these characteristics helps explain why dust explosions are a significant concern in industries that handle or generate combustible dust.