No one is sure how the ancient Egyptians built the pyramids near Cairo. But a new study suggests they used a little rock‘n'roll. Long-ago builders could have attached wooden pole s to the stones and rolled then across the sand, the scientists say.
“Technically, I think what they're proposing is possible,” physicist Daniel Bonn said.
People have long puzzled over how the Egyptians moved such huge rocks. And there's no obvious answer. On average, each of the two million big stones weighed about as much as a large pickup truck. The Egyptians somehow moved the stone blocks to the pyramid site from about one kilometer away.
The most popular view is that Egyptian workers slid the blocks along smooth paths. Many scientists suspect workers first would have put the blocks on sleds(滑板). Then they would have dragged them along paths. To make the work easier, workers may have lubricated the paths either with wet clay or with the fat from cattle. Bonn has now tested this idea by building small sleds and dragging heavy objects over sand.
Evidence from the sand supports this idea. Researchers found small amounts of fat, as well as a large amount of stone and the remains of paths.

However, physicist Joseph West thinks there might have been a simpler way , who led the new study . West said , “I was inspired while watching a television program showing how sleds might have helped with pyramid construction . I thought , ‘Why don't they just try rolling the things?'“A square could be turned into a rough sort of wheel by attaching wooden poles to its sides , he realized . That , he notes , should make a block of stone” a lot easier to roll than a square”.
So he tried it.
He and his students tied some poles to each of four sides of a 30-kilogram stone block. That action turned the block into somewhat a wheel. Then they placed the block on the ground.
They wrapped one end of a rope around the block and pulled. The researchers found they could easily roll the block along different kinds of paths. They calculated that rolling the block required about as much force as moving it along a slippery(滑的)path.
West hasn't tested his idea on larger blocks, but he thinks rolling has clear advantages over sliding. At least, workers wouldn't have needed to carry cattle fat or water to smooth the paths.

New App Helps People Remember Faces

    Large gatherings such as weddings and conferences can be socially overwhelming. Pressure to learn people's names only adds to the stress. A new facial-recognition app could come to the rescue, but privacy experts recommend proceeding with caution.

    The app, called SocialRecall, connects names with faces via smartphone cameras and facial recognition, potentially avoiding the need for formal introductions. "It breaks down these social barriers we all have when meeting somebody," says Barry Sandrew, who created the app and tested it at an event attended by about 1,000 people.

    After receiving an invitation to download SocialRecall from an event organizer, the user is asked to take two selfies and sign in via social media. At the event, the app is active within a previously defined geographical area. When a user points his or her phone camera at an attendee's face, the app identifies the individual, displays the person's name, and links to his or her social media profile. To protect privacy, it recognizes only those who have agreed to participate. And the app's creators say it automatically deletes users' data after an event.

    Ann Cavoukian, a privacy expert who runs the Privacy by Design Center of Excellence praises the app's creators for these protective measures. She cautions, however, that when people choose to share their personal information with the app, they should know that "there may be unintended consequences down the road with that information being used in another context that might come back to bite you."

    The start-up has also developed a version of the app for individuals who suffer from prosopagnosia, or "face blindness," a condition that prevents people from recognizing individuals they have met. To use this app, a person first acquires an image of someone's face, from either the smartphone's camera or a photograph, and then tags it with a name. When the camera spots that same face in real life, the previously entered information is displayed. The collected data are stored only on a user's phone, according to the team behind the app.

    Though pigs may never fly, a two-year-old pig in Franschhoek, South Africa is proving they sure can paint! Meet Pigcasso, the world's first known pig artist whose masterpieces are selling for thousands of dollars to benefit Farm Sanctuary S. A. , Africa's only registered shelter for rescued farm animals.

    Joanne Lefson, who saved Pigcasso from a slaughterhouse(屠宰场) two years ago, discovered the animal's artistic talent accidentally. The South African activist says, of the numerous toys presented to keep the then four-week-old piglet entertained, it was the paintbrushes that seemed to attract her the most. "They were the only thing she didn't eat," Lefson quips.

    The rescuer decided to present the pig with canvas and paint and see what happened. To her delight, Pigcasso began creating works of art that can best be described as "abstract expressionism". Now weighing a hefty(重量）450 pounds, the celebrated pig, who loves to paint the area's scenic landscapes, has a dedicated "studio" at Farm Sanctuary S.A. where she resides. Lefson says, "I do not force her to paint. She paints when she wants to."

    Pigcasso's artwork, which has thus far been sold online, is currently on display at Cape Town's picturesque Victoria ~ Alfred Waterfront. Dubbed "Oink", the pop-up exhibition will run through March 5before heading to London-Paris-Berlin, and Amsterdam. Lefson says its main aim is to highlight the effect of animal agriculture on the planet and inspire change.

    While Pigcasso is the first pig and first nonhuman to headline an exhibition, she is not the first animal to create masterpieces. Elephants, sea lions, and even penguins have shown similar artistic talent--in exchange for some treats, of course!

Magical History Tour

    Join us for our fifth annual exploration of fascinating historic sites around Greater Portland that you've never seen or maybe didn't even know existed! The Magical History Tour is your key to unlocking fascinating historical places that are not usually open to the public. It is a self­guided adventure guaranteed to amaze and amuse both adults and children. Equipped with a map, and at your own pace, you will be greeted by guides at each location ready to share the history of the tour stop.

    In the 5th year of the Magical History Tour, we will be presenting an exciting mix of both new sites and favorites from the past four years.

    The Magical History Tour check in begins at 9: 45 am at Maine Historical Society's Brown Library. At this time, you will find out where the tour will take you as you receive your map and ticket into each site.

    Follow us on Facebook, Twitter, and Instagram for updates, chances to win tickets and some other exciting opportunities; and feel free to share your tour experiences to our social media pages using # MHStour!

    ●Time: 10: 00 am—4: 00 pm, Saturday, May 11, 2019

    ●Location: 485 Congress Street

    ●Tickets: Get your tickets online, by calling us at 207­774­1 822, or by visiting our Museum Store at 489 Congress Street. $25／Adult  MHS  Member; $35／Adult General Admission; $5／Juniors under age 18.

    ●Volunteering: We need volunteers for the Magical History Tour! Volunteers help for half the day of the tour and are given a free ticket to the tour to enjoy either before or after their volunteer shift!

    For more information, email us at events@mainehistory org or call us at 207­774­1822.

    What do you want to be when you grow up? A teacher? A doctor? How about an ice-cream taster?

    Yes, there really is a job where you can get paid to taste ice cream. Just ask John Harrison, an "Official Taste Tester" for the past 21 years. Testing helps producers to be sure of a product's quality. During his career Harrison has been responsible for approving large quantities of the sweet ice cream –as well as for developing over 75 flavors(味道).

    Some people think that it would be easy to do this job; after all, you just have to like ice cream, right? No –-- there's more to the job than that, says Harrison, who has a degree in chemistry. He points out that a dairy or food-science degree would be very useful to someone wanting a career in this "cool" field.

    In a typical morning on the job, Harrison tastes and rates 60 ice-cream samples. He lets the ice cream warm up to about 12 F. Harrisonexplains, "You get more flavor from warmer ice cream, which is why some kids like to stir it, creating ice-cream soup."

    While the ice cream warms up, Harrison looks over the samples and grades each one on its appearance. "Tasting begins with the eyes," he explains. He checks to see if the ice cream is attractive and asks himself, "Does the product have the colour expected from that flavor?" Next it's time to taste!

    Continuing to think up new ideas, try out new flavors, and test samples from so many kinds of ice cream each day keeps Harrison busy but happy – working at once cool job.

Human rubbish can be a cockatoo's (凤头鹦鹉) treasure. In Sydney, the birds have learned how to open dustbins and throw rubbish around in the streets as they hunt for leftovers. People are now fighting back.

When cockatoos learn how to open dustbin lids (盖子), people change their behavior, using things like bricks to weigh down lids, to protect their trash from being thrown about. That's usually a low-level protection and then the cockatoos figure out how to defeat that. That's when people strengthen their efforts, and the cycle continues.

Tricks such as attempting to scare the parrots off with rubber snakes don't work very well. Nor does blocking access with heavy objects such as bricks; cockatoos use force to push them off. Hanging weights from the front of the lid or placing items such as sneakers and sticks through a bin's back handles work better. Researchers didn't see any birds get inside bins with these higher levels of protection.

The findings suggest an arms race, but the missing piece is how the birds will respond as people try new ways of blocking bins. Some survey responses suggest that the parrots are learning.

Cockatoos may stay away from strategies that take too long to beat. Bricks, for instance, are easy to quickly push off a bin; breaking sticks placed through the bin's back handle could take more time. Perhaps if enough people in a neighborhood adopt a highly effective method, Clark. a behavioral ecologist says, the cockatoos may not find it worth it to stop by.