Category Archives: Students

Items for students and others, interested in learning about science and engineering and the application of science in our lives. We post many of the general interest items here.

The Sahara Wasn’t Always a Desert

Green Sahara

For much of the past 70,000 years, the Sahara has closely resembled the desert it is today. Some 12,000 years ago, however, a wobble in the Earth’s axis and other factors caused Africa’s seasonal monsoons to shift slightly north, bringing new rains to an area nearly the size of the contiguous United States. Lush watersheds stretched across the Sahara, from Egypt to Mauritania, drawing animal life and eventually people.

by some 3,500 years ago the desert had returned. The people vanished.

The twilight of the Green Sahara around 4,500 years ago might have been the perfect time to be hunting at Gobero, said Carlo Giraudi, the team’s geologist. As water sources dried up throughout the region, animals would have been drawn to pocket wetlands, making them easier to kill. Four middens found on the dunes and dated to around that time included hundreds of animal remains, as well as fish bones and clamshells—not usually part of a herder’s diet. “The Green Sahara’s climate was rapidly changing,” said Giraudi, “but just before the lake dried up, the people at Gobero would have thought they were living in a golden period.”

There are many values of science: letting our curious minds learn, giving us cool robots and gadgets and letting us learn about the past (and thus about the ever-changing world we live in).

Related: Ancient Whale Uncovered in Egyptian DesertRare Saharan Cheetahs Photographed“Gladiator” tomb is found in Rome

Boa Constrictor Gives Birth to Clones

Snake gives ‘virgin birth’ to extraordinary babies

A female boa constrictor snake has given birth to two litters of extraordinary offspring. Evidence suggests the mother snake has had multiple virgin births, producing 22 baby snakes that have no father. More than that, the genetic make-up of the baby snakes is unlike any previously recorded among vertebrates, the group which includes almost all animals with a backbone.

“All offspring are female. The offspring share only half the mother’s genetic make-up,” he told the BBC.

Humans for example have X or Y sex chromosomes; females have two X chromosomes and males have a combination of an X and a Y chromosome. In place of X and Y, snakes and many other reptiles have Z and W chromosomes.

In all snakes, ZZ produces males and ZW produces females. Bizarrely, all the snakes in these litters were WW. This was further proof that the snakes inherited all their genetic material from their mother, as only females carry the W chromosome.

“Essentially they are half clones of their mother,” says Dr Booth. That is because the baby snakes have inherited two copies of one half of their mother’s chromosomes, including one W chromosome.

More astonishing though, is that no vertebrate animal in which the females carry the odd sex chromosome (in this case the W chromosome) has ever been recorded naturally producing viable WW offspring via a virgin birth.

“For decades WW has been considered non-viable” says Dr Booth. In such species, all known examples of babies that are the product of parthenogenesis are male, carrying a ZZ chromosomal arrangement.

Related: No sex for all-girl fish speciesVirgin Birth for Another Shark SpeciesBdelloid Rotifers Abandoned Sex 100 Million Years AgoWorld’s Smallest Snake Found in BarbadosAndrogenesis

Driver Thanks Engineer Who Hit Him on Purpose

Driver thanks man who hit him on purpose

Driving to a Mariners game, Duane Innes saw a pickup ahead of him drift across lanes of traffic, sideswipe a concrete barrier and continue forward on the inside shoulder at about 40 mph. A manager of Boeing’s F22 fighter-jet program [and engineer by training], Innes dodged the truck, then looked back to see that the driver was slumped over the wheel. He knew a busy intersection was just ahead, and he had to act fast.

“Basic physics: If I could get in front of him and let him hit me, the delta difference in speed would just be a few miles an hour, and we could slow down together,” Innes explained. So he pulled in front of the pickup, allowed it to rear-end his minivan and brought both vehicles safely to a stop in the pull-off lane.

Some might say the driver of the truck, 80-year-old Bill Pace, of Bellevue, and anyone Pace’s truck might have slammed into had luck on their side that day. A retiree who volunteers for Special Olympics and organizes food drives, Pace didn’t know it at the time, but he’d had a minor heart attack two days earlier and his circulation was so poor he passed out at the wheel with his foot resting on the accelerator.

Nice story and nice that the article had a tiny bit of science in the story, with another example of good work by an engineer.

Related: Nikola Tesla, A Scientist and EngineerWhat is an Engineer?Statistics Insights for Scientists and EngineersInspirational Engineer

Science and Optical Illusions

illusion with color tiles on a cubeMore illusions by R Beau Lotto, lecturer in neuroscience, University College London

The middle tiles on the cube both have the same color, even though they appear very different to most of us.

The science of optical illusions

the two physically identical tiles do indeed now look very different.

Why? The information in the image strongly suggests that the dark brown tile on the top now means a poorly reflective surface under bright light, whereas the bright orange one at the side means a highly reflective surface in shadow.
… [from another illusion]
So why do they look so different? Because your brain takes the image on the retina and creates what it sees according to what the information would have meant in the brain’s past experience of interacting with the world.

In this case the angles suggest depth and perspective and the brain believes the green table is longer than it is while the red table appears squarer.

The beautiful thing about illusions is they make us realise things are never what they seem, and that our experiences of the world shape our understanding of it.

Studying illusions can teach us several things. We can learn that it is easy for our senses to be fooled. We can learn about how the brain works. We can also learn how to take into account how our brain works to try and adjust our opinions (to be careful we are not just interpreting things incorrectly). It is amazing to see some of the wild guidance our brains give us. Normally they do a fantastic job of guiding us through our day but they have weaknesses that can lead us to mistaken conclusions.

Related: Albert Einstein, Marylin Monroe Hybrid ImageWhy Does the Moon Appear Larger on the Horizon?Illusions, Optical and OtherSeeing Patterns Where None Exists

sOccket: Power Through Play

In a fun example of appropriate technology and innovation 4 college students have created a football (soccer ball) that is charged as you play with it. The ball uses an inductive coil mechanism to generate energy, thanks in part to a novel Engineering Sciences course, Idea Translation. They are beta testing the ball in Africa: the current prototypes can provide light 3 hours of LED light after less than 10 minutes of play. Jessica Matthews ’10, Jessica Lin ’09, Hemali Thakkara ’11 and Julia Silverman ’10 (see photo) created the eco-friendly ball when they all were undergraduates at Harvard College.

photo of sOccket creators: Jessica Matthews, Jessica Lin, Hemali Thakkara and Julia Silverman

sOccket creators: Jessica Matthews, Jessica Lin, Hemali Thakkara and Julia Silverman

They received funding from: Harvard Institute for Global Health and the Clinton Global Initiative University. The

sOccket won the Popular Mechanics Breakthrough Award, which recognizes the innovators and products poised to change the world. A future model could be used to charge a cell phone.

From Take part: approximately 1.5 billion people worldwide use kerosene to light their homes. “Not only is kerosene expensive, but its flames are dangerous and the smoke poses serious health risks,” says Lin. Respiratory infections account for the largest percentage of childhood deaths in developing nations—more than AIDS and malaria.

Related: High school team presenting a project they completed to create a solution to provide clean waterWater Pump Merry-go-RoundEngineering a Better World: Bike Corn-ShellerGreen Technology Innovation by College Engineering Students

Watch a June 2010 interview on the ball:
Continue reading

The DIY Movement Revives Learning by Doing

School for Hackers

The ideal educational environment for kids, observes Peter Gray, a professor of psychology at Boston College who studies the way children learn, is one that includes “the opportunity to mess around with objects of all sorts, and to try to build things.” Countless experiments have shown that young children are far more interested in objects they can control than in those they cannot control—a behavioral tendency that persists. In her review of research on project-based learning (a hands-on, experience-based approach to education), Diane McGrath, former editor of the Journal of Computer Science Education, reports that project-based students do as well as (and sometimes better than) traditionally educated students on standardized tests, and that they “learn research skills, understand the subject matter at a deeper level than do their traditional counterparts, and are more deeply engaged in their work.” In The Upside of Irrationality, Dan Ariely, a behavioral psychologist at Duke University, recounts his experiments with students about DIY’s effect on well-being and concludes that creating more of the things we use in daily life measurably increases our “feelings of pride and ownership.” In the long run, it also changes for the better our patterns of thinking and learning.

Unfortunately, says Gray, our schools don’t teach kids how to make things, but instead train them to become scholars, “in the narrowest sense of the word, meaning someone who spends their time reading and writing. Of course, most people are not scholars. We survive by doing things.”

I am a big believer in fostering kids natural desire to learn by teaching through tinkering.

Related: Build Your Own Tabletop Interactive Multi-touch ComputerHome Engineering: Building a HovercraftScience Toys You Can Make With Your KidsHands-on High School Engineering Education in MinnesotaAutomatic Cat Feeder

Understanding the Chemistry Behind Cooking

Video either broken by bigthink or their system is extremely poor causing minutes of failure to load 🙁 Removed.

The science behind cooking is very interesting. I would have been more interested in cooking if I was exposed to more of this early on in my life.

Related: The Man Who Unboiled an EggDon’t Eat What Doesn’t RotRethinking the Food Production SystemThe Calorie DelusionTracking the Ecosystem Within Us

Friday Fun: Aerodynamics for Sports

“Impossible” Soccer Kick Leads to New Physics Equation

The amazing goal — which left French goalkeeper Fabien Barthez too stunned to react — was scored during a friendly match in the run up to the 1998 World Cup. A group of French scientists, perhaps desperate to prove that at least the laws of physics weren’t actively rooting against their national team, have been able to figure out the trajectory of the ball and, with it, an equation to describe its unusual path.

It all comes down to the fact that, when a sphere spins, its trajectory is a spiral. Usually, gravity and the relatively short distance the ball travels cover up this spiral trajectory, but Carlos was a mere 115 feet away and kicked the ball hard enough to reveal its true spiral-like path.

In this open access paper, the spinning ball spiral, the authors explore the science behind ball paths in different situations.

one can identify sports dominated by aerodynamics (table tennis, golf and tennis) and sports dominated by gravity (basketball and handball). In between, we find sports where both gravity and aerodynamics play a comparable role (soccer, volleyball and baseball). Indeed, in the first category of sports, the spin is systematically used, while it is not relevant in the second category, and it only appears occasionally in the third one, in order to produce surprising trajectories.

Related: Friday Fun: Amazing GoalThe Science of the Football SwerveEngineering a Better Football