The surprisingly simple way Egyptians moved massive pyramid stones without modern technology

By Terrence McCoy May 2, 2014

Few have traveled to the pyramids of Egypt and not wondered how an ancient civilization without modern technology could have constructed structures so large they can be viewed from space. Some have theorized they were built inside out.

On the flakier side, some say aliens did it.

Perhaps the most confounding mystery of all involves how incredibly large stones made their way to the middle of the desert without massive mechanical assistance. No camel, even the Egyptian kind, is that strong.

The truth, researchers at the University of Amsterdam announced this week in a study published in the journal Physical Review Letters, may actually be quite simple. It has long been believed that Egyptians used wooden sleds to haul the stone, but until now it hasn’t been entirely understood how they overcame the problem of friction. It amounts to nothing more, scientists say, than a “clever trick.”

They likely wet the sand. “For the construction of the pyramids, the ancient Egyptians had to transport heavy blocks of stone and large statues across the desert,” the university said. “The Egyptians therefore placed the heavy objects on a sledge that workers pulled over the sand. Research … revealed that the Egyptians probably made the desert sand in front of the sledge wet.”

It has to do with physics. The sort of sledges the Egyptians used to transport the two-ton loads of stone were pretty rudimentary. They were wooden planks with upturned edges. Dragging something that heavy through hot sand would — unsurprisingly — dig into the grains, creating a sand berm that would make progress nearly impossible. It “was perhaps observed by the Egyptians that in [a] dry case, a heap of sand forms in front of the sled before it can really start to move,” says the study, authored by a team of eight researchers led by Daniel Bonn.

The only way around that problem would be to constantly clear the sand out of the way, making a tedious process even more tedious.

Damp sand, however, operates very differently. According to the research, “sliding friction on sand is greatly reduced by the addition of some — but not that much — water.” So this time, researchers placed a laboratory version of an Egyptian sledge in a bin of sand that had been dried in the oven. Then they threw down some water, and measured the grains’ stiffness. If the water had the appropriate level of wetness, something called “capillary bridges” — extremely small droplets of water that glue together individual grains of sand — would form.

These bridges not only stopped the sled from forming sand berms but also cut by half the amount of force required to move the cart. “I was very surprised by the amount the pulling force could be reduced — by as much as 50 percent — meaning that the Egyptians needed only half the men to pull over wet sand as compared to dry,” Bonn told The Washington Post.

Indeed, he says the experiments showed the required force decreased in proportion to the sand’s stiffness. “In the presence of the correct quantity of water, wet desert sand is about twice as stiff as dry sand,” the university says. “A sledge glides far more easily over firm desert sand simply because the sand does not pile up in front of the sledge as it does in the case of dry sand.”

Too much water, however, would create separate problems. “The static friction progressively decreases in amplitude when more water is added to the system,” the study says……

*USING WATER IN ANCIENT TECH

*USING WATER TO BUILD 'CAPILLARY BRIDGES"

** Bridges, Watch the Water, Ancient Tech

You can’t squeeze blood from a stone, but wringing water from the desert sky is now possible, thanks to a new spongelike device that uses sunlight to suck water vapor from air, even in low humidity. The device can produce nearly 3 liters of water per day for every kilogram of spongelike absorber it contains, and researchers say future versions will be even better. That means homes in the driest parts of the world could soon have a solar-powered appliance capable of delivering all the water they need, offering relief to billions of people.

The new water harvester is made of metal organic framework crystals pressed into a thin sheet of copper metal and placed between a solar absorber (above) and a condenser plate (below). WANG LABORATORY AT MIT

There are an estimated 13 trillion liters of water floating in the atmosphere at any one time, equivalent to 10% of all of the freshwater in our planet’s lakes and rivers. Over the years, researchers have developed ways to grab a few trickles, such as using fine nets to wick water from fog banks, or power-hungry dehumidifiers to condense it out of the air. But both approaches require either very humid air or far too much electricity to be broadly useful.

To find an all-purpose solution, researchers led by Omar Yaghi, a chemist at the University of California, Berkeley, turned to a family of crystalline powders called metal organic frameworks, or MOFs. Yaghi developed the first MOFs—porous crystals that form continuous 3D networks—more than 20 years ago. The networks assemble in a Tinkertoy-like fashion from metal atoms that act as the hubs and sticklike organic compounds that link the hubs together. By choosing different metals and organics, chemists can dial in the properties of each MOF, controlling what gases bind to them, and how strongly they hold on.

Over the past 2 decades chemists have synthesized more than 20,000 MOFs, each with unique molecule-grabbing properties. For example, Yaghi and others recently designed MOFs that absorb—and later release—methane, making them a type of high-capacity gas tank for natural gas–powered vehicles.

In 2014, Yaghi and his colleagues synthesized a MOF that excelled at absorbing water, even under low-humidity conditions. That led him to reach out to Evelyn Wang, a mechanical engineer at the Massachusetts Institute of Technology (MIT) in Cambridge, with whom he had previously worked on a project to use MOFs in automobile air conditioning. After synthesizing the new zirconium-based MOF, dubbed MOF-801, Yaghi met Wang at MIT and said, “Evelyn we have to come up with a water-harvesting device.” She agreed to give it a shot.

The system Wang and her students designed consists of a kilogram of dust-sized MOF crystals pressed into a thin sheet of porous copper metal. That sheet is placed between a solar absorber and a condenser plate and positioned inside a chamber. At night the chamber is opened, allowing ambient air to diffuse through the porous MOF and water molecules to stick to its interior surfaces, gathering in groups of eight to form tiny cubic droplets. In the morning, the chamber is closed, and sunlight entering through a window on top of the device then heats up the MOF, which liberates the water droplets and drives them—as vapor—toward the cooler condenser. The temperature difference, as well as the high humidity inside the chamber, causes the vapor to condense as liquid water, which drips into a collector. The setup works so well that it pulls 2.8 liters of water out of the air per day for every kilogram of MOF it contained, the Berkeley and MIT team reports today in Science.

“It has been a longstanding dream” to harvest water from desert air, says Mercouri Kanatzidis, a chemist at Northwestern University in Evanston, Illinois, who wasn’t involved with the work. “This demonstration … is a significant proof of concept.” It’s also one that Yaghi says has plenty of room for improvement. For starters, zirconium costs $150 a kilogram, making water-harvesting devices too expensive to be broadly useful. However, Yaghi says his group has already had early success in designing water-grabbing MOFs that replace zirconium with aluminum, a metal that is 100 times cheaper. That could make future water harvesters cheap enough not only to slake the thirst of people in arid regions, but perhaps even supply water to farmers in the desert.

*Update, 14 March, 12:28 p.m.: This item has been updated to reflect the fact that the device pulls nearly 3 liters of water out of the air for every kilogram of the water-absorbing material that is used.

https://www.sciencemag.org/news/2017/04/new-solar-powered-device-can-pull-water-straight-desert-air

https://www.sciencemag.org/news/2017/04/new-solar-powered-device-can-pull-water-straight-desert-air

*watch the water

What Happened When The US Government Confiscated Guns For "Safety & Protection" In The Past?

Here's a little bit of history to think about. December 29, 2012 marked the 122nd Anniversary of the murder of 297 Sioux Indians at Wounded Knee Creek on the Pine Ridge Indian Reservation in South Dakota .

These 297 people, in their winter camp, were murdered by federal agents and members of the 7th Cavalry who had come to confiscate their firearms “for their own safety and protection.”

The slaughter began after the majority of the Sioux had peacefully turned in their firearms. The Cavalry began shooting, and managed to wipe out the entire camp. 200 of the 297 victims were women and children.

Far too many times, unjust gun control bills were passed and signed into law under the guise of “for your safety” or “for protection.” The Patriot Act signed into law by G.W. Bush, was expanded and continues under Barack Obama. It is just one of many examples of American citizens being stripped of their rights and privacy for “safety.” Now, the right to keep and bear arms is on the table, and will, most likely be attacked to facilitate the path for the removal of our firearms, all in the name of “our safety.”

Before any American citizen blindly accepts whatever new firearms legislation that is about to be doled out, they should stop and think about something for just one minute-

Evil does exist in our world. It always has and always will.

Throughout history evil people have committed evil acts. In the Bible, one of the first stories is that of Cain killing his brother Abel. We can not legislate “evil” into extinction. Good people will abide by the law, and the criminal element will always find a way around it.

Evil exists all around us, but looking back at the historical record of the past 200 years, across the globe, where is “evil” and “malevolence” most often found? In the hands of those with the power, the government. The greatest human tragedies on record and the largest loss of innocent human life can be attributed to governments. Who do the governments always target? “Scapegoats” and “enemies” within their own borders, but only after they have been disarmed to the point where they are no longer a threat. Ask any Native American, and they will tell you it was inferior technology and lack of arms that contributed to their demise. Ask any Armenian why it was so easy for the Turks to exterminate millions of them, and they will answer “We were disarmed before it happened.” Ask any Jew what Hitler’s first step prior to the mass murders of the Holocaust was and they will tell you it was confiscation of firearms from the people.

Wounded Knee is the prime example of why the Second Amendment exists and why we should vehemently resist any attempts to infringe on our rights to bear arms. Without the Second Amendment we will be totally stripped of any ability to defend ourselves and our families

WOUNDED KNEE THE FIRST MASSACRE IN AMERICAN HISTORY OF "DISARMED' PEACEFUL NATIVE AMERICANS

apparently not such good human rights record ourselves…. this point in history stands as the reason for the existence of the second amendment

>>5695160

sauce

https://freedomoutpost.com/what-happened-when-the-us-government-confiscated-guns-for-safety-protection-in-the-past/