“I am a Scientist!” Day

On Friday I had the pleasure of talking to about 60 fifth graders from Robinson Elementary School in Redondo Beach. The school was having its annual “I am a Scientist!” Day which gets students excited about science through fun demonstrations and talks from members of the science community. The presentations this year included a wide-variety of topics such as the science of magic, science and engineering in a refinery, robotics, and matter and reactions. 
   My talk was about physics. We learned that physics is the study of matter and energy, that matter is anything that takes up space and has mass, and that energy is the ability to do work. I told them that Einstein is regarded as the father of modern physics because he was able to relate matter and energy through his world-famous equation. 

The air flow from the wing of this airplane is shown
by colored smoke rising from the ground. The swirl
at the wingtip traces the aircraft’s wake vortex.

   Then we talked a bit about fluid mechanics, the study of fluids and the forces acting on them. As an example I talked about a program created by NASA and the Federal Aviation Administration in 1990 where they studied wake vortexes. The swirling airflow from the wingtip of an airplane is its wake vortex, which exerts a powerful influence on the airflow behind the plane. Because of wake vortex, the FAA requires aircraft to keep a minimum distance between each other when they land and take off. The goal of the program was to boost airport capacity by determining conditions under which planes could fly closer together. They studied wake vortexes using wind tunnels, flight tests and supercomputers in order to fully understand the phenomenon. Then they used what they learned to create an automated system that could predict changing wake vortex conditions at airports. For example, they confirmed that pilots don’t have to worry as much about wake vortex in rough weather because turbulent, windy conditions cause them to dissipate more quickly. 
   Afterwards, we did a neat demonstration of how to create a vortex using a closed cardboard box with a circle cut out of the side and a fog machine. Everyone in the class was able to create a vortex and use it to knock over a stacked pyramid of styrofoam cups. It was a fun day and I was very impressed by how knowledgeable the kids were. Also, a big thanks to my daughter Daniella who was my capable assistant for the day. Hopefully we can do it again next year!

Water on the Moon

LCROSS mapping of the lunar south pole showing
Cabeus and Shackleton craters, which have been
found to contain ice.

There is water on the Moon—lots of it. Permanently-shadowed craters at both poles have been trapping and accumulating ice for billions of years, research has shown. These cold traps contain at least 600 million tons of ice according to research done over the last few years. 
   Concentrated stores of ice on the Moon could revolutionize space travel. Lunar ice could be mined and split into its component elements hydrogen and oxygen to make rocket fuel, then brought to low Earth orbit and sold. An orbiting filling station could spur a wave of space travel because spaceships wouldn’t have to bring all the fuel they need from Earth. Considering that it costs about $10,000 to put one kilogram of payload into low earth orbit, there is a huge incentive to set up a mining camp on the Moon to tap these vast deposits of water to create a sustainable expansion into space.
   The lunar poles are unique because they have craters that never get a drop of sunlight, making them super cold. Shackleton crater, named after the famous Antarctic explorer Ernest Shackleton, is one that has been studied in detail. Situated at the Moon’s south pole, the interior of Shackleton crater is in permanent shadow. Also, the rim of this crater is in constant sunlight, making it an ideal location as a lunar outpost. Sunlight on the rim could provide energy for solar panels which in turn could provide the energy needed to harvest the water in the crater, and NASA is planning on setting up an outpost there by 2020. NASA’s Lunar Reconnaissance Orbiter (LRO) probed this impact crater with radar back in 2009. Shackleton crater was a good candidate because it is so massive—4.2 km deep and 21 km across, making it one of the deepest crater on the Moon. By analyzing the reflections off Shackleton crater, researchers discovered that is contains radar-transparent material which is consistent with ice. 

   Several other Moon missions have corroborated the existence of water on the Moon. In 2008, India’s Chandrayaan-1 spacecraft found evidence of water molecules on the lunar surface by deploying an impact probe onto the surface of the moon and then flying through the cloud of debris it kicked up. Chandrayaan-1 also mapped the moon with radar from 2008 to 2009 and found that the polar regions contained ice within the depths of permanently-shadowed craters. In 2009, the Lunar Crater Observation and Sensing Satellite (LCROSS) also discovered water and ice kicked up after an impact probe smashed into the Cabeus crater near the Moon’s south pole.

Science vs. Engineering

A solar furnace in France.

Scientists explore the world around us and make discoveries about the universe and how it works. Engineers then apply that knowledge to solve real-world problems, usually with the goal of optimizing cost and efficiency. In other words, if science is the discovery of what is possible, then engineering takes that knowledge and makes it economical.
   For example, a few weeks ago I wrote about a process for making eco-friendly cement. Researchers from George Washington University developed what they called Solar Thermal Electrochemical Production (STEP), which eliminates carbon dioxide from the cement-production process. The claim was that not only would it be more eco-friendly, but also less expensive than traditional methods. STEP would use solar energy in two ways. It would eliminate the needs for fossil fuels by using solar thermal energy to melt the limestone. It would also use solar energy to electrolyze the melt to produce lime (the main ingredient in cement), oxygen and carbon monoxide. 
   Scientifically, a very interesting idea. But let’s play devil’s advocate and take a closer look with our engineering hardhat on. Even if something can be done experimentally, it's a far cry from being profitable in the short term. One drawback of the STEP process is that it adds complexity to the production of cement, which is rarely cost-effective. 
   The research claims that by selling the carbon monoxide by-product, they could make $300 per ton of cement produced. I view this claim with suspicion. Carbon monoxide has a small and specialized market when sold by the bottle, so if this process was implemented broadly, the demand for this by-product would drop sharply. Most carbon monoxide that is currently needed is produced on-site to avoid shipping costs.
   Another point to consider is whether or not the STEP process could be portable. Most cement made today is produced by trailer-mounted units that are taken to the quarry and assembled in the field. By making the cement on-site it eliminates the need to transport tons of raw materials, especially for cement where it takes about five tons of raw materials to make one ton of finished product. It's hard to envision how a vast array of solar panels and mirrors could be transported and assembled efficiently. Another potential problem with solar power is that solar panels work best in a dust-free environment. Cement production creates a lot of dust and it would be difficult to keep the solar panels clean and operating at maximum efficiency. Also, it goes without saying that this process would not work too well in colder climates.
   One of the truths of scientific research is that much of it never ends up as part of a real production process. That’s just the nature of the game. But even if only one idea in a hundred is successful, it’s worth the price in my opinion. And even if an idea ends up not being feasible, sometimes it will lead to another discovery. Even plastic was invented by accident in an attempt to create a cheap substitute for shellac.

A STEP in the Right Direction

Cement is made by a process known as calcination. By heating limestone (CaCO₃) with small quantities of other materials such as clay to 800 °C in a kiln, carbon dioxide (CO₂) is expelled from the calcium carbonate to form lime (CaO), which is then blended with the other materials that have been included in the mix. The resulting material, called clinker, is then ground and mixed with a small amount of gypsum into a powder to make Portland cement, the main ingredient in concrete.

   When limestone is processed this way, the greenhouse gas carbon dioxide is an unfortunate by-product. Cement manufacturing is responsible for up to 7% of global greenhouse gas emissions, releasing about 9 kg of carbon dioxide for every 10 kg of cement produced. Global production of cement is about 3.3 billion tons per year which creates about three billion tons of greenhouse gasses each year.

   Researchers at George Washington University have devised a greener technique: Solar Thermal Electrochemical Production (STEP), which eliminates carbon dioxide production from the process. It is also less expensive than calcination. For cement, STEP would use solar energy in two ways. The STEP method eliminates the needs for fossil fuels by instead using solar thermal energy to melt the limestone. Then it can assist with electrolysis. Electrolysis of the melt produces lime, oxygen and carbon—and no carbon dioxide.

   When STEP is run at higher temperatures, it creates carbon monoxide which can be used for industrial applications, such as in fuels, plastics or pharmaceuticals. If cement were created this way, the sale of the by-products could net up to about $300 per ton of STEP-created cement. Compare that with a cost of $70 per ton to produce cement via traditional methods, and its not hard to see that STEP is a step in the right direction. The challenge now is to scale up the process for commercialization. Cement manufacturers are already looking for ways to reduce their greenhouse gas emissions, so if the process can be adapted for industrial use it could transform the industry.

James Cameron Explores the Mariana Trench

The Mariana Trench in comparison with Mount Everest.

James Cameron, the director of mega blockbusters Avatar and Titanic, has reached the depths of the Mariana Trench, a decent of nearly 11 km below sea level. He accomplished this in a 7.3-meter submersible designed to reach the bottom of Challenger Deep, the deepest place on Earth. Cameron is the first person to explore Challenger Deep—located south of Guam in the Pacific Ocean—in a single-person submersible, and recorded this incredible feat on March 26, 2012.
   Upon resurfacing, Cameron was cheered by his team members. “We all did it, I was just the [unlucky one] that had to get crammed in here to go take the ride,” Cameron exclaimed. Speaking to reporters, Cameron described his journey: “My feeling was one of complete isolation from all of humanity. I felt as though literally in the space of one day, I’ve gone to another planet and come back.”
   The dive follows seven years of planning, including the design and construction of a specialized submarine that could withstand the incredible pressure at the ocean floor, which actually squeezes the sub so much that it reduces its overall length by several centimeters.
   It took Cameron 2 hours and 37 minutes to reach the bottom and only 70 minute to come back up. Cameron spent a little more than three hours at the bottom of the Mariana Trench before returning. A malfunction in the hydraulic system kept him from bringing back most of his sediment sample. He wasn’t able to close the sample door and lost most of it on the trip back to the surface. Still, Cameron was hopeful that some new microbial species would be found in what he was able to bring back.
   The Mariana Trench is so remote that we don’t know even the basic of what is down there, other than small invertebrates and arthropods. Scientists do not know, for example, if there are any fish that far down. The only other time that Challenger Deep has been explored was in 1960 when Jacques Piccard, a Swiss oceanographer, and Don Walsh, a U.S. Navy captain, explored the bottom for 20 minutes in the bathyscaphe Trieste. They also had to cut their mission short when they found cracks developing in their viewing window. Piccard passed away in 2008, but Walsh was one of the team members on hand for Cameron’s historic dive.

The Higgs Field

A simulated event in the Large Hadron Collider
where two protons collide to produce a Higgs boson.

Recently, there has been a lot of chatter amongst physicists about the Higgs boson. But what is it? In 1964, a physicist named Peter Higgs proposed the existence of an energy field that permeated the entire universe. We now call this energy field the Higgs field. The reason he proposed this field is that nobody understood why some subatomic particles were very massive while other had little or no mass. The energy field that Higgs proposed would interact with the subatomic particles and give them their mass. Very massive particles would interact a lot with the field, while massless particles wouldn’t interact at all. 
   To better understand the idea we can use an analogy of swimmers in the ocean. If we think of the ocean as a Higgs field, then a fish, being streamlined, only interacts slightly with the field and can move through it very easily. A fish, therefore, would be similar to a low-mass particle. In contrast, if you or I were to try and swim through the same water, we would move much more slowly. We would represent a massive particle because we interact a lot with the water.
   The lightest of the subatomic particles is the electron, and the heaviest is the top quark, which weighs about as much as an entire gold atom, or about 350,000 times more than the electron. The thinking is not that the top quark is more massive because it is bigger. In fact, it’s the same size as an electron, but more massive because it interacts more strongly with the Higgs field. If the Higgs field didn’t exist, neither of these particles would have any mass at all.
   For some reason, we don’t hear much about the Higgs field, but rather the Higgs boson. The two are related because the Higgs boson is the smallest part of the Higgs field. We can use our water analogy to understand this better. We all know what water is. If you are in the ocean, you know that water is a continuous medium that is all around you. We also know that water is made of molecules. Once you realize that water is composed of countless water molecules you can begin to appreciate the Higgs boson. The Higgs field consists of countless Higgs bosons.
   Keep in mind that the Higgs boson has not been discovered yet. Even so, physicists are currently studying data taken from particle accelerators such as the Large Hadron Collider at CERN, in Geneva, Switzerland, and we should have an answer soon. If it is confirmed we will have the final piece of the jigsaw puzzle known as the Standard Model in place. If not, well, then things get really interesting!

Thor’s Nuclear Hammer

Use of thorium instead of uranium may be breakthrough in energy production. Recently, India has announced their intent to produce nuclear power using thorium. The thorium reactor under development would be the first of its kind.
   The development of workable, industrial-scale thorium reactors has for decades been a dream for nuclear engineers and environmentalists alike with the hope that it becomes a major alternative to fossil fuels. Thorium has considerable advantages over uranium. Thorium is more abundant and using it does not involve releasing large quantities of carbon dioxide, making it less harmful to the climate than fossil fuels.
   The Bhabha Atomic Research Center (BARC) in Mumbai is finalizing the site for construction of a new large-scale experimental reactor. If all goes according to plan, the reactor could be operational by the end of the decade. The reactor is designed to produce 300 megawatts of electricity—about one fourth of the output of a typical nuclear plant.

   Producing a workable thorium reactor would be a huge breakthrough in energy production. Using thorium—a moderately radioactive element named after Thor, the Norse god of thunder—as a source for nuclear power is not new technology. Early research carried out in the U.S. during the 1950s and 60s was promising, but abandoned in favor of using uranium. Some believe this is at least partly because nuclear power programs in developed countries produce plutonium as a byproduct which can be used to create nuclear weapons. Unlike uranium, thorium reactors do not produce plutonium. Also, the waste from thorium reactors is less dangerous and remains radioactive for hundreds rather than thousands of years. For governments worried about nuclear waste and the possibility of terrorists getting their hands on plutonium, this is a distinct advantage. 
   Another reason for the attention on thorium is that the world’s supply of uranium is being rapidly depleted. Thorium is more than three times as abundant and contains 200 times as much energy density compared to uranium. India has the largest thorium deposits in the world, nearly 40% of the world’s supply, giving them additional incentive to develop the technology for export.
   One potential problem is that thorium reactors need a trigger fuel to initiate operation. Usually plutonium is used as a trigger fuel, but that could pose a problem for import and export. New reactors will eventually be developed to use low-enriched uranium as a trigger fuel which will make it much easier to market the technology abroad.
   Kirk Sorensen, a spokesperson for Teledyne Brown Engineering and former NASA aerospace engineer, sums up thorium’s potential “Conflicts that we see today based around energy could go away. Thorium energy sources don’t emit carbon dioxide or greenhouse gasses, and don’t produce dangerous waste. It could enable us to have cleaner water, cleaner air, and less intrusion on our environment.”