A Letter to the 18+ STEAM Aficionados:

by Paola Salazar

PC: The Franklin Institute, Adults-Only Event guests

Please let it be known that you have not been forgotten! We have a lot of great events lined up for our more mature members in the CSF community. In fact, we’ve rounded up a couple of favorite events just for you!

I mean really, who ever said we were too old to find STEAM fun?

Homo naledi: A new Homo Species Shrouded in Mysteries

By Paola Salazar

Picture this: a woman covered head to toe in dirt and debris, her hair in a ponytail under a helmet, loose long clothing enveloping her lanky body, her hand reaching up to her cheek to wipe away sweat.

She’s wearing a helmet with a big bright flashlight attached to the front, and as she approaches a crack in the ground ahead of her, she switches the flashlight on. The fissure is about 7.5 inches wide, and is the entryway to a cave system that’s about 30 meters deep.

Robert Clark/National Geographic: Lee Berger’s daughter, part of the excavation team (left). Paola Salazar/Facebook/American Association of Physical Anthropologists: The FB announcement from Lee Berger (right).

This is one of the “underground astronauts” who flew to South Africa’s Cradle of Humankind when in 2013, paleoanthropologist Lee Berger announced the need for researchers who could fit into the cave entrance of what would then be known as the home of a newly discovered extant species related to modern humans, the Rising Star Cave. 

It’s through her and a team of five other female explorers that two years later, Berger was able to announce last Thursday that after two excavations, the results of their efforts was a whopping 1,550 hominid bones--hominid meaning humans and their fossil ancestors--and what’s more, that these fossils were attributed to at least 15 members of a new species, Homo naledi.

The researchers say that the species had a brain about the size of an orange, stood about 5 feet tall, and weighed about 100 lbs. They've also revealed more on its anatomy within their paper, published on the journal eLife.

Homo naledi/Witswatersrand University

But first of all, what exactly is a paleoanthropologist?

A paleoanthropologist is someone interested in studying, finding and/or analyzing modern human’s ancestors--human-like creatures known as hominids that, depending on how old they are, may still have some ape-like features.

Hominids come in two different genera, which is the general name for species or animals that are more closely related to each other than to other species--like how dogs are related to wolves and cats are related to wildcats under the same genera--Canis and Felis, respectively.

Depending on which anthropologist you ask, there are generally two genera for human ancestors: Australopithecus, for earlier and much older ancestors, and Homo, for the more recently extinct species and the current species, Homo sapiens. While paleoanthropologists have currently discovered numerous species related to humans, in each of the different species groups, they don’t have very many individual examples of each.

This is part of what makes the Rising Star Cave so unique--15 individuals were found! Not only that, but they found some that were children, some that were adults and even the elderly.

During the excavations back in late 2013 and early 2014, Berger and his research team shared much about the process of the excavation. They also provided an exciting day-by-day number count of the amount of bones being collected that started wowing interested parties across the globe from the very beginning (see the NatGeo blog here).

Most researchers will only release such information over time or with the actual publication itself, which can take years. However, Berger and his fellow researchers on the analysis and excavation teams strongly support open scientific communication with the public.

Still, he left one very important question unanswered: what was it? Was it a close relative to humans? Was it an australopithecine?

And now that Berger finally revealed the identity of Homo naledi...he then left many new questions for us to ponder!

So we at the Cambridge Science Festival tried getting some answers from one of the researchers, former Boston University professor, Jeremy DeSilva, who is now an associate professor at Dartmouth College in New Hampshire.

One of the new bits of mind-boggling information we got from Berger was the suggestion that the cave itself, being so far deep into a larger cave system (see here) was actually being used as a burial site by Homo naledi during its time as a living species.

    National Geographic: The fossils were found in the Dinaledi Chamber--look how far down that is!

National Geographic

DeSilva explained that while this idea was the first of its kind for species this old (since most signs of purposefully burying the dead are about 100,000 years ago), it was the only one they could seem to fit with the evidence they have so far.

“The thing is, with cave sites, we can usually tell what the caves are used for. For example, if there are signs of bite marks on the bones found and if we find bones of other animals that are not hominids, then we know it was likely a dump site for predators. Here, we really only found Homo naledi--that’s it.” Any animal bones found were higher up within the cave system.

He also said that there was sedimentation between each different fossil group that they found, meaning that after revealing one set of bones, the next set of bones would be another layer or two of digging below.

To top it off, there’s also ways of telling if the bones got there by natural causes like landslides, or perhaps rain carried sediment further down the cave system, and the bones traveled with it. Again, there was no sign of this on the site!

Another odd thing about the site was that they weren’t able to date when Homo naledi was actually walking around on land, which is information that’s highly important for researchers trying to figure out the significance of the discovery.This is again because of the fact that Homo naledi was found by itself, or isolated, from other signs of life during its time.

See, having the bones of other animals would mean that the researchers could analyze those bones as well, trace where and when in time that animal was alive, and be able to tell from there when Homo naledi was alive.

But because there were no animals found with the Homo naledi fossils, and because cave dirt and mud is very hard to analyze for dating purposes as well, the researchers won’t be able to date Homo naledi until they’re done analyzing its bones and can “sacrifice” one to someone on the team who can analyze the bone directly to date it.

“When this guy was walking around makes a big difference,” DeSilva said. “If it was older than 2 million years old, then it could be the earliest member of the Homo genus; if it’s around 2 million years old then it’s adding to the collection of cousins to modern humans; and if it’s younger than 1 million years old then that’s huge, because it could mean that earlier versions of modern humans weren’t the only ones walking around at the time,” DeSilva explained, since right now, that is what human evolutionary history suggests.

Still, DeSilva said that going by its anatomy, he does not think Homo naledi would be younger than 1 million years old--though he admits he’d be excited if it was.

Aside from the significance of when exactly they were alive, something else that’s intriguing about Homo naledi is that whenever it is that they were walking around, they actually walked around with features that were still somewhat primitive (more ape-like), which is odd for something that has so many human-like features.

For example, their shoulders and slightly more curved fingers suggest that they were still much better at climbing than we are now. Were they climbing in trees or through caves? Was it for shelter or to escape predators?

That’s also unknown, unfortunately, according to DeSilva, who specializes in the functional morphology (how and why bones look the way they do) of foot bones and the lower limbs. He said there aren’t enough studies on the biomechanics of cave or rock climbers--meaning we don’t fully understand the range of motion that cave/rock climbers use, or what kind of forces they exert on their bones, or how those forces affect the shape and density of their bones after years of climbing in that way.

DeSilva said that while the big reveal has just happened now, they’ve already spent the last year focusing on more detailed analyses related to how Homo naledi lived: how it walked (this is what he and a few others are working on), what it ate, trying to see if they can recover any DNA, and more.

While they work towards better defining Homo naledi, the release has brought criticism from other researchers as well, due to disagreement on whether or not Homo naledi is actually a new species or an addition of specimen for an already known early Homo species.

The research team welcomes the criticism though, and has even made the fossils available online (link at the bottom) to anyone wanting to see the fossils out of curiosity or out of the desire to find evidence for whatever is believed to be incorrect in their conclusions. They did this because in addition to their open-access mentalities, they realize that some of the conclusions they made after careful consideration of what was discovered are hard to wrap our heads around--burials, new species, its features, dating, etc.

“There’s no doubt that this is a significant find,” DeSilva said. “But without the date, we can’t fully tell just how significant it is.”

“It absolutely questions what makes us human,” Lee Berger said in an interview for CNN, “And I don’t think we know anymore.”

Berger, his fellow researchers, and South African leaders and government officials suggest that one of the more important aspects about the discovery is that it introduces or reignites people’s interest in human origins, field work, and science in general across generations.

Speaking to a group of high schoolers for the World Science Festival, Berger said younger generations are crucial to making even more discoveries not just in technology, but out in the open.

“We need [these] generation[s] to get out from behind those computers and start exploring,” Berger said, “Even areas where we think we know what’s there, because there are still things to be discovered.”

Want to see the actual bones? Click here!

For more on Homo naledi, the researchers, and the excavation, click here!

Want to see and read more on how hominids move? Catch more info from Prof. DeSilva here!


Paola is a Boston-based science journalist with a background in social and life sciences.

How Does the Brain Work?

By Paola Salazar

 The Curiosity Challenge

Why is the sun yellow? Why do grass and dirt have a stronger scent after it rains? How and why do my nails keep growing? What is a black hole?

A while back, we offered children and teens an opportunity to submit questions related to any topic in science, tech, engineering and mathematics that they may have, and here we've done it again. 
  
The Curiosity Challenge for ages 5-14 encourages curiosity.  We ask the students to enter their question about the world in whatever form - essay, poem, drawing, photograph.  All good science starts with our curiosity and questions of the world around us.  This series of blog posts will highlight some of the questions we have received through the Curiosity Challenge and some answers to them.


We’ve reached out to graduate students and researchers in each field, and have begun getting some great feedback on some the questions we all wonder at some point in time.

So without further ado, here’s round one of the Curiosity Challenge Q&A!

How Does the Brain Work?

Alex Lee, Age 11

[http://chinwag.com/files/images/general/brain_works.jpg]

A long time ago, long before there were dogs or monkeys or people, the planet was mostly covered in very simple organisms like worms. As the worms got bigger, they realized they had a problem - the head of the worm might want to go in one direction, but it had no way to communicate with the tail of the worm to get the tail to go in the same direction.

The worms figured out that they would be much more successful if they had a special kind of cell that communicated between the head and the tail to coordinate movement. We now call these kinds of communication cells "neurons." As animals became more and more complicated, they got more and more neurons and the neurons had to be connected in more complicated ways in order to successfully control the body.

The brain is the end product of that process of evolution - a highly sophisticated organ that coordinates your movement and your thoughts. Our brains now do many other things, like keeping memory and emotion. We still don’t fully understand how these things work in the brain though. If you become a neuroscientist, one day you could figure out how the brain works and add to what we know!

Responder: Communicating Science @ MIT (commit.mit.edu), a student group at MIT

Paola is a Boston-based science journalist with a background in social and life sciences.

A Berry Efficient Solar Cell

A short walk through the Cambridge Science Festival will reveal an important fact: the festival is not just for science. It’s for technology, presentations of innovative ideas, and fun, hands-on activities. The CSF offers such a wide variety of activities that it has attracted cool, sometimes strange, modern technologies. Among the strangest is the blackberry solar cell - no, not a solar cell for the BlackBerry phone, we’re talking about the actual fruit - small seeded dark berries whose juice can be used to harvest energy from the sun. To see this technology in action and make a solar sell for yourself (for free!) head over to

the Cambridge Public Library at 449 Broadway between 12:30pm - 1:30pm or 2:00pm - 3:00pm for “The Blackberry Solar Cell: A green Chemistry Activity.” This activity is definitely for all ages.

If blackberries can be used to capture solar energy, what other unusual uses might fruit have? Perhaps a postage stamp made out of lemon rind, or a dress made out of apples?

An investigation of the many uses of fruit first reveals the most common uses: food, beverages, gifts and decorations. After all, where would we be without grape juice, fruit baskets, and holly at Christmas?

After a bit more research, increasingly unusual uses for fruit show up. Some uses seem to be completely unrelated to fruit. The following products are good examples: various type of pain killers - opium which contains morphine and codeine is made from the fruits of opium poppy; dyes - cherries and walnuts can be used as natural dyes; musical instruments - gourds are dried and hollowed out to make instruments; skin care products - supposedly, applesauce makes a great facial mask; and leather polish - banana rinds will do the trick!

Looking further into fruity practices, medicinal applications seem quite common. It is amusing, or possibly disturbing, that nearly every fruit has been claimed to have some medicinal benefit. Cranberries heal UTIs, rose apples are a brain and liver stimulant, figs cure warts, and goji berries boost your immune system. This widespread claim that “fruit is medicine” either suggests that fruits are generally good for one’s health and contain vitamins and minerals that promote wellness, or it suggests that people are desperate in the search for cures to yet incurable diseases. Most effects of fruit on health are not scientifically, clinically, or even methodically tested/proven to be beneficial. Therefore claims of healing fruit should be taken with a grain of salt whereas a product like a solar cell can be shown to work without doubt. Either way, it can’t be denied that fruit has had a large effect on the health of the world, whether as a medicine or simply a good source of nutrition.

After taking a look at some alternative uses of fruit, a blackberry solar cell is undoubtedly the most unique. Imagine a small electronic device whose materials include (1) indium tin oxide conducting glass, (2) iodide electrolyte solution, and (3) blackberry juice. That third ingredient is slightly shocking! However, the blackberry juice plays an important role in the solar cell, acting as a dye that first absorbs the light from the sun that the solar cell can then convert to electricity. If you’d like to see this for yourself, head over to the Blackberry Solar Cell event.

It's pretty clear that fruit is not common in electronics. Why would someone think to use blackberry juice as a solar cell? In an increasingly green society, looking toward more natural and non-toxic materials is beneficial for the inventor and the environment. This presents an opportunity to introduce more natural products into modern technology, like trees grown for biomass to create renewable energy, or corn grown for ethanol. These green technologies already exist. What will be next?

Apple dress adapted from this photograph.

STOP THROWING AWAY ELECTRICITY!

The Truth about Phantom Loads

It’s possible that you might be paying for extra electricity without knowing it. You may have already cut back on your energy consumption in the typical ways, replacing light bulbs and purchasing energy-efficient appliances. Test your knowledge of home energy efficiency at the Energy Efficiency Game Show from 12:00 noon - 4:00 pm on Saturday April 24th at Cambridge Public Library, 449 Broadway, as part of the Science Carnival at the Cambridge Science Festival.

So is it possible that you might still be paying more for electricity than you actually use? Imagine this scenario: settling down on the sofa during a calm winter evening, you turn on your energy efficient floor lamp to begin peacefully reading,

Green Your Home All-In-One: For Dummies.

Just as you get to an exciting section on combination compost/recycling units, an intrusively loud noise erupts from the neighbor’s open window ripping into your thoughts. You look with disgust at their wide-screen television (150 watts) playing on full volume while their gas fireplace (1,500 watts) sends heat into the room and straight out the open window. Every light inside the house is on, not to mention they

are using incandescent bulbs (1,000 watts). The microwave (1,000 watts)

is heating some leftovers that you assume have been in the refrigerator (100 watts) for at least a week

while their

• cell phones charge (20 watts)

• their computers compute (100 watts)

• the DVD system plays (20 watts)

• the printer prints (50 watts)

• and the dishwasher washes (1200 watts)

GRAND TOTAL OF VERY UN-GREEN NEIGHBOR’S POWER CONSUMPTION: (5,140 watts!!!)

5,140 watts is the power you’d use to do 17 pushups per second. That’s 1000 pushups per minute! If they had to power their own house by doing pushups, at least they’d be in shape.

Your neighbor is wasting so much electricity, yet you manage a measly total of 10 watts just for your reading light. (You are wearing a parka because you don’t use heating anymore, and you gave also up refrigerated foods.) When you turn out the lights to call it a night, you think you’re using no power at all. Think again! It turns out the devices you have plugged in are using electricity without your knowing it. Your television and your microwave are off and yet they are leaking power from the outlets. They are acting as phantom loads.

Phantom Loads

Phantom Loads, also known as standby power, leaking electricity or vampire power, is the power that leaks into electronic appliances even when they are in the off or standby mode. Most electronics operate in standby mode the majority of the time, yet are still using power. A desktop computer for example uses 21 watts in sleep mode. When it is completely powered off, it still uses about 3 watts. You’d have to unplug the computer completely to stop this leakage! Take a look at this website for leakage rates of some typical household appliances.

Living in a house without heat or refrigeration, as in the scenario above, might be unreasonable. However, adding up the leaking power from some common appliances give surprising results.

These phantom loads total up to 23 watts with all appliance completely off. Sleep mode can add another 15 watts to a computer or 10 watts to a DVD player. The average US house uses around 1000 watts which means phantom loads account for more than 2% of the energy used by households. By some estimates (http://www.aceee.org/pubs/a981.htm), phantom loads comprised 5% of the entire US household power consumption amounting to a total of $3.5 billion dollars annually spent on wasted power. If the quantity of wasted power isn’t shocking enough, the amount of wasted money should be.

How the phantoms be stopped?

Surge protectors help. Plugging appliances into surge protectors and then shutting these off at night will eliminate phantom loads. Alternatively, unplugging the appliance would do the trick. Also, shutting electronic gadgets off completely rather than leaving them on sleep or standby cuts power consumption enormously. Again, replacing appliances with energy-efficient versions is a good way to contribute to energy conservation and to save $$.

This website tells you how you can check whether your home has phantom loads

http://www.kouba-cavallo.com/phantom.html

Check out these websites for more information on phantom loads:

http://www1.eere.energy.gov/consumer/tips/home_office.html

http://www.aceee.org/pubs/a981.htm

http://www.energy-saving-electronics.info/standby-power.htm