Humid air is lighter than dry air. The two hydrogen molecules in H2O make the molecul lighter than air’s other constituents. We’ve all read and heard about how the fog was thick, the humid air was heavy and so forth. This is the epitome of literary license. Trust me, dry air is heavy air.

There are many units of measure to express the pressure of air at a point on earth. I commonly use pounds per square inch largely because I’ve use Imperial measurements all my life (over 70 years) and am MUCH more comfortable with them, well with most of them. Show me someone comfortable with the slug and I’ll show you a better man than me.

Sea level atmospheric pressure in different units of measure:

PSIG                    14.7 PSI

Bar                       1 Bar

Millibar                 1013.25

Pa                         ~101,325?

Hpa                      1013.25

Torr (mmHg)         760

Inches Hg              29.92

During the days of sailing ships the mercury manometer was the only reliable instrument and could even be manufactured and calibrated on-board ship at sea with a sealed glass tube and some mercury (probably from the broken manometer.) The nautical necessities of centuries past continue to this day so barometric pressure is most often expressed in inches of mercury or inHg.

Barometric pressure is a common measure of the water in the air. High pressure, over about 30 inches of mercury indicates means that there is little water in the air making it heavy. Low pressure, under 30 inches of mercury, means the air is humid, making it light.

Hurricane air pressure and forecaster isobar charts are often expressed in millibars (mb) or Hectopascals (hPa).

Most weather occurs in the bottom 1,000 ft of altitude. The worst tornadoes work within a couple of hundred feet of the ground. Some of the strongest tornadoes utilize buoyant air from less than 10 feet above the ground.

Ground level pressure is the result of all the air pressure above a point. The air pressure at sea level is 14.7 Pounds per Square Inch Gauge[i] (PSIG) of air, more or less. This means there is 14.7 pounds of air above each square foot of ground or water at sea level.

Air pressure at 1,000 ft altitude is about 14.2 PSIG. A one-foot square column of air between 0 ft altitude and 1,000 ft altitude weighs 0.5 PSI. Therefore, the bottom 1,000-foot column of air at sea level weighs about 0.5 pounds (14.7 PSIG – 14.2 PSIG) or 3.5% of the air.

Thus, it follows that the bottom 3.5 % of the atmosphere is responsible for local weather.

It turns out that the change in buoyancy of dry air between 20 degrees C and 35 degrees C is about 3.5%. Nothing sinister but I bet you’ll remember those two numbers.

That value will be helpful while discussing and understanding air buoyancy in later topics.

[i] Author’s note –

The gauge suffix indicates the pressure value is referenced to a vacuum such as in outer space. This is sometimes absolute pressure.

Justice American Style

One of the crowning jewels of American Society is its judicial system.

BULLSHIT

The American Judicial system is for sale to the highest bidder or most influential special interest group. By influential, I mean the group with the greatest number of votes in their pocket. I am going to emphasize two widely publicized criminal trials that I happened to watch due to medical recuperation and retirement. I will attempt to make the case that politics was the predominant factor in each trial, one successful and the other unsuccessful at attaining the desired political result. In both cases, the defendant’s bank account was the deciding factor.

The two types of political theorists are the purists and the rational. The purists believe the ‘system’ is nearly fool proof and only a few more laws will make the process of adjudication perfect. The rational realize that no matter how much the written law is improved a human element is involved.

An unbiased source of information will attempt to tell the story without bias for either the prosecution or defense.

I wish to illustrate my point with two very high profile trials. I suspect that if you know the facts you will agree with my opinions.

Similarities

The similarities between the trials are a high profile defendant and victim, a concerted effort to find the defendant guilty, a lot of pretrial publicity, saturated television coverage and potential creation of a political advantage. The possibility of community or even national unrest due to the verdict was a possible outcome of the trial. The state is invested maximum monetary and personnel assets into getting a conviction in both trials.

Differences

In one case, the defendant was rich black man by my standards while the other defendant was a public servant whom worked two jobs just to make ends meet. In one trial, the public was satisfied with the verdict while in the other the public was dissatisfied with the verdict.

 

 

 

OJ Simpson	Derek Chauvin
Similarities
Maximum effort by state	Maximum effort by state
Extensive pretrial publicity	Extensive pretrial publicity
Extensive TV coverage	Extensive TV coverage
Possibility of unrest due to verdict	Possibility of unrest due to verdict
Differences
High profile defendant	High profile victim
Public dissatisfaction with verdict	Public satisfaction with verdict
Black defendant	White defendant
DNA evidence	Video evidence
Inept prosecutors	Effective prosecutors
Effective defense	Overwhelmed defense
Read about the OJ Simpson trial.	Read about the Derek Chauvin trial.

The OJ Simpson trial was televised for nearly nine months in the mid-1990s and involved accusations of him killing his wife and a visitor.

I have a description of each trial as well as my personal observations. In both cases, I changed my opinion as I watched the trial. I thought OJ Simpson was guilty of murder but found myself unconvinced at trial’s end. I though Derek Chauvin was guilty of murder and found myself convinced that Mr. Chauvin was guilty of manslaughter at most and probably innocent at the end.

I am a white baby boomer. My personal political opinions make me a foreign affairs conservative and domestic liberal. I am a liberal because I believe individual liberty. Modern liberals believe in the government’s liberty to suppress the individual’s liberty. I believe monopolies should be discouraged, especially if government chartered. I believe that all individuals have equal rights despite skin color, ethnicity, religion or any other characteristics. If the welfare of the man and the community are different, there is a big problem. I believe that individuals have a responsibility to resist corruption, especially aristocracy – note that this includes politicians with too much power. I believe in state’s rights.