11/21/10

The Science of... Flash #109

Here's another entry looking at the science behind the principles mentioned in the Flash Comics of the 1960's.  In Flash #109 the Mirror Master returns and uses his mirrors again to befuddle both The Flash, and inadvertently Barry Allen.  Even as a kid I could see the "science" of the Mirror Master was pure fantasy, but there were some other aspects of the plot that have some roots in reality.

Air Resistance - The Mirror Master uses a special mirror to shrink The Flash so he's knee-high to a mouse. As he avoids the villain the Flash tumbles from the top of a building, but as the editor notes "It is a fact that tiny animals can fall from great heights without injury! This is because of the slight weight and the buoyancy of the air!"
 
There is a problem with this "fact." The force that slowed Flash's fall isn't the "buoyancy" of the air, since it would have to be the "the net upward buoyancy force is equal to the magnitude of the weight of fluid displaced by the body." In that case The Flash would be swimming in the air, yet we can see in panel that he's falling. The editor must have been thinking of air resistance, or drag. Wikipedia defines drag as "forces that oppose the relative motion of an object through a liquid or gas." So, as The Flash falls, the air resistances slows his descent.

Radiation - The last panel is packed with internal dialogue as Flash explains how he'll use "certain radiation" to grow back to his full size. A quick search on the internet shows that, yes, some amphibians, fungus, and plants grow larger under UV or infrared radiation, but the same search will also yield results showing that some tumors can grow and metastasize under similar radiation. Hopefully The Flash knows what he's doing, since he's full size a page later where we see my favorite "Flash Fact."

 

Tornado Forces - As the Flash erupts a wall the editor notes "just as a tornado-driven straw can penetrate several feet of solid oak, so can Flash at super-speed penetrate solid walls!" This was one of my most favorite Flash facts, as well as a convenient mechanism for speeding up the action. I mean, this "fact" gave the Flash the ability to run through walls -- way cooler than Superman bursting through the wall.  Fortunately for us we're dealing with fiction, since this ability is about as realistic as time-travel.

It's true that a tornado has a lot of force, and can send field grass flying at speeds greater than 200 mph. But most evidence and experimentation doesn't show that the straws pass through trees without harm to either object. MythBusters had an episode dedicated to answering the question whether the grass could go through the tree. In their experiment the grassy missile penetrated less than an inch into the tree.
"Propelling a piece of straw at a palm tree at a distance of 50cm at 320mph (the world record for recorded wind speed at ground level), the straw only managed to penetrate the tree a quarter of an inch. Even firing at the tree while it was bent (to increase the size of the pores in the surface of the tree) at point blank range added no additional distance into the tree. A piece of reed was tested as the sturdiest organic object that might be mistaken for a piece of straw. At both ranges, the reed only managed to go about two inches into the tree. Additionally, Jamie tried a piece of piano wire, and at 50 cm, it flew not only through the tree but through a sheet of plywood on the wall behind it, partially embedding itself into the cement wall."

Regardless of whether the straw could pass through the tree, if the Flash tried to use his super speed to zip through a wall, he'd probably end up partially embedded in it, or considering that he doesn't quite have the same structure as a reed, maybe splattered against it.
Actual straws that thought they were The Flash
Interestingly, during my web search I found I school in Texas that has a research lab studying the effect of wind-generated debris on structures. The lab has a device that shoots lumber, PVC pipes and steel rebar into fabricated walls. Perhaps the Flash should read their report before he tries that trick again.


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