Are Humans Still Getting Taller?

You've probably noticed, either from museum exhibits or visits to colonial houses, that humans these days are generally taller than we used to be. In fact, over the last 150 years, the average height of people in industrialized nations has increased approximately 10 centimeters (about four inches).  In the first half of the 18th century, the average height of an English male was 165 cm (5 ft 5 in) and the average height of an Irish male was 168 cm (5 ft 6 in). American men at the time were taller. By the following century, they'd have an extra 3-9 cm on their European counterparts. These days, the male population in England measures in at 175.4 cm (5 ft 9 in) while the U.S. still has them beat with an average height of 177.6 cm (5 ft 10 in).

When you consider all of human history, this species-wide growth spurt is actually a rather new phenomenon. Prior to that, average heights were variable based on particular environmental and socioeconomic factors. For example, low population density during the Middle Ages meant abundant food and, consequently, taller people.

But are people still getting taller? Will we eventually have to rebuild all our infrastructure and raise the height of basketball hoops? Most likely not. Our increasing height seems to have leveled off lately, and while there will always be outliers, this is probably as tall as we get as a species. To understand why that is, we have to first understand why we started growing in the first place.

The answer is relatively straightforward and harkens back to the Middle Ages example. Easier access to better food and healthcare since the mid-1900s have allowed people to develop to their full physical potential. Modern science and technology led to improvements in childhood nutrition and fewer childhood illnesses, which also drove height up. This is corroborated by the fact that historically, conditions of poor access to sufficient food are well correlated to shorter populations.

But now that most people in industrial countries are not suffering from malnutrition or epidemics, the human population has settled at a relatively stable average height. Which is probably good for architects and basketball hoop manufacturers.

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Big Questions
What’s the Difference Between Prison and Jail?
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Many people use the terms jail and prison interchangeably, and while both terms refer to areas where people are held, there's a substantial difference between the two methods of incarceration. Where a person who is accused of a crime is held, and for how long, is a factor in determining the difference between the two—and whether a person is held in a jail or a prison is largely determined by the severity of the crime they have committed.

A jail (or, for our British friends, a gaol) refers to a small, temporary holding facility—run by local governments and supervised by county sheriff departments—that is designed to detain recently arrested people who have committed a minor offense or misdemeanor. A person can also be held in jail for an extended period of time if the sentence for their offense is less than a year. There are currently 3163 local jail facilities in the United States.

A jail is different from the similarly temporary “lockup”—sort of like “pre-jail”—which is located in local police departments and holds offenders unable to post bail, people arrested for public drunkenness who are kept until they are sober, or, most importantly, offenders waiting to be processed into the jail system.

A prison, on the other hand, is usually a large state- or federal-run facility meant to house people convicted of a serious crime or felony, and whose sentences for those crimes surpass 365 days. A prison could also be called a “penitentiary,” among other names.

To be put in a state prison, a person must be convicted of breaking a state law. To be put in a federal prison, a person must be convicted of breaking federal law. Basic amenities in a prison are more extensive than in a jail because, obviously, an inmate is likely to spend more than a year of his or her life confined inside a prison. As of 2012, there were 4575 operating prisons in the U.S.—the most in the world. The country with the second highest number of operating prisons is Russia, which has just 1029 facilities.

Have you got a Big Question you'd like us to answer? If so, let us know by emailing us at bigquestions@mentalfloss.com.

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Big Questions
What Do Morticians Do With the Blood They Take Out of Dead Bodies?
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Zoe-Anne Barcellos:

The blood goes down the sink drain, into the sewer system.

I am not a mortician, but I work for a medical examiner/coroner. During an autopsy, most blood is drained from the decedent. This is not on purpose, but a result of gravity. Later a mortician may or may not embalm, depending on the wishes of the family.

Autopsies are done on a table that has a drain at one end; this drain is placed over a sink—a regular sink, with a garbage disposal in it. The blood and bodily fluids just drain down the table, into the sink, and down the drain. This goes into the sewer, like every other sink and toilet, and (usually) goes to a water treatment plant.

You may be thinking that this is biohazardous waste and needs to be treated differently. [If] we can’t put oil, or chemicals (like formalin) down the drains due to regulations, why is blood not treated similarly? I would assume because it is effectively handled by the water treatment plants. If it wasn’t, I am sure the regulations would be changed.

Now any items that are soiled with blood—those cannot be thrown away in the regular trash. Most clothing worn by the decedent is either retained for evidence or released with the decedent to the funeral home—even if they were bloody.

But any gauze, medical tubing, papers, etc. that have blood or bodily fluids on them must be thrown away into a biohazardous trash. These are lined with bright red trash liners, and these are placed in a specially marked box and taped closed. These boxes are stacked up in the garage until they are picked up by a specialty garbage company. I am not sure, but I am pretty sure they are incinerated.

Additionally anything sharp or pointy—like needles, scalpels, etc.—must go into a rigid “sharps” container. When they are 2/3 full we just toss these into one of the biotrash containers.

The biotrash is treated differently, as, if it went to a landfill, then the blood (and therefore the bloodborne pathogens like Hepatitis and HIV) could be exposed to people or animals. Rain could wash it into untreated water systems.

This post originally appeared on Quora. Click here to view.

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