Sunday, July 31, 2011

The Ice Diet

Today let’s examine the science behind the claim that you can lose weight by eating ice. The theory is this: eating ice will make the body burn up calories in order to maintain a constant body temperature. Seems reasonable, but let’s explore.
  The calorie is a unit of energy and is approximately equal to the amount of energy required to raise the temperature of one gram of water by one degree Celsius at standard atmospheric pressure. I say approximately because it varies slightly depending on the starting temperature of water and if contains any impurities or dissolved gasses. Even though the standard unit of energy in the SI system has been the joule since 1960, it has not caught on yet when talking about food energy (one calorie is about 4.2 J).
  So lets calculate how much ice you would have to eat in order to lose one kilogram. First we have to make a few assumptions: 1) The ice temperature is near 0° C.  2) The body will efficiently metabolize stored energy in order to melt the ice and raise its temperature to 37° C, the average body temperature for humans. 3) The actual mass of the ice consumed does not count towards our final weight.
  So for one gram of ice, the total energy needed to bring it to 37° C is 37 calories to raise its temperature plus another 80 calories to change it from solid ice to liquid water. This is known as its specific melting heat. Therefore, the total energy required is 117 calories. In order to lose one kilogram of body mass you have to reduce calorie intake by 7,700 Calories, so it looks like one would only have to eat 66 grams of ice, right? Well, there is one last detail. What we normally refer to as a calorie when talking about food is really a kilocalorie (1 kilocalorie = 1,000 calories, often written as 1 Calorie). So in actuality, instead of eating 66 grams of ice you would need to eat 66 kilograms of ice. Good luck!

Thursday, July 21, 2011

Mount Evans

Mount Evans Highway is the highest paved road in North America.

We will be heading back home tomorrow and one stop we are planning on making along the way is Mount Evans, Colorado. The drive up Mount Evans is called the road into the sky. From 2,300 m at Idaho Spring you climb to 4,300 m at the summit, driving through three altitudinal life zones: montane, subalpine and alpine.
  Montane means "of the mountain" and the montane zone is characterized by higher rainfall than the adjacent lowlands. It is usually well forested, being far below the tree line. 
  As you approach the tree line, you transition into the subalpine life zone. Here the trees usually become crooked and gnarled due to continual exposure to freezing winds which cause vegetation to become deformed. Here trees need to be sheltered by rocks or snow cover in order to survive. Typically these trees are of the fir, spruce or pine varieties and they are called Krummholz formation, from the German words krumm (crooked, bent, twisted) and holz (wood). Well established krummholz trees can live up to a thousand years. Grasses and shrubs are also found in the subalpine life zone.
  Above the tree line is the alpine life zone which is characterized by tundra. Here vegetation is close to the ground and consists of grasses, sedges and dwarf shrubs covered with lichens and mosses. Plants have to adapt to the harsh winds and cold temperatures of the alpine life zone in order to survive.
  Next week I will continue with more on Mount Evans and talk about the fauna which can be seen in each life zone.

Hoping to see some of the famous Mount Evans mountain goats!

Saturday, July 16, 2011

The Fremonts

My two “research assistants” at a Fremont
Indian State Park petroglyph site.

I’m on vacation this week and I wanted to share a postscript to an earlier column I wrote on the Fremont Indians. I had a chance to stop at another Fremont site on my way to Iowa, this one at Fremont Indian State Park near Sevier, Utah at Clear Creek Canyon.
   The site was discovered during construction of Interstate 70, and thousands of artifacts have been excavated from the ancient village and put on permanent display at the museum there.

   The Fremont Indians lived from about AD 400 to 1,300 in north and central Utah as well as in parts of Nevada, Colorado and Idaho. They were hunter-gatherers who were influenced by the Anasazi, who introduced corn and pottery which made it possible for them to settle. Clear Creek Canyon was rich in food resources which meant they spent less time hunting and gathering and had more leisure time which they used to make jewelry and other items to trade with other tribes and gave them time to create the rock art that adorns the cliff-sides today.
   The Fremont diet consisted mainly of corn, beans and squash which was harvested and stored in granaries. They supplemented this with wild grasses, nuts and berries as well as an assortment of animals such as deer and rabbits. The granaries were made of rock and adobe, and were designed to keep out vermin and protect the harvest. While some granaries were built near their homes, others were hidden away in remote locations, often high up on the cliff sides in order to protect the grain from being stolen. 
A close-up of one of the thousands of Fremont petroglyphs 
that can be seen at Fremont Indian State Park.
   The artifacts found included arrowheads, pottery, and grinding stones called manos and metates used to grind their corn into a course meal. Analysis of the teeth of the Fremont indicates that their teeth were badly worn, likely from eating corn flour with bits of rock that wore off during grinding.
   The Fremonts are often compared to the Anasazi, whom they traded with. Although they lived in the southwest at the same time, there are some significant differences. The Fremonts lived in single-room pithouses and lived in small villages. The Anasazi built larger houses, often multi-story, and they lived in large villages with many families. The Anasazi also built round, ceremonial structures while the Fremont did not.

Thursday, July 7, 2011

A Tale of Two Theories

We’re well aware of Charles Darwin and his theory of natural selection which he published in his landmark 1859 book, On the Evolution of Species. But he was not the only one to develop this theory. Similar ideas were also being developed during this time by Alfred Wallace, a self-educated naturalist from Wales. 
Starting in 1848, Wallace spent four years in the Amazon on an expedition he had organized to collect specimens for rich collectors and museums. As luck would have it, his return ship caught fire and sank. He spent the next ten days at sea in an open boat before being rescued. Unfortunately, almost all his specimens were lost. And though he was disheartened and vowed to never travel again, two years later he was off to the East Indies on an incredible odyssey that would consume him for the next eight years as he amassed over 125,000 specimens. During this time he identified the dividing line between Asian and Australian fauna which is known as the “Wallace Line”, prompting some to dub him the father of biogeography. 
The Darwin-Wallace Medal was first issued by the
Linnean society to Alfred Wallace on the 50th
anniversary of the reading of Darwin and Wallace’s
papers on natural selection.
In 1855, Wallace put together some of his ideas and discoveries in a paper that outlined the principles of evolution. Darwin was initially unimpressed after reading the paper, but it did prompt him to start putting together his own book on evolution. In 1858, Wallace sent another paper to Darwin. Although he was weak with malaria, he had experienced an epiphany regarding natural selection: that because populations would always outgrow their food supply, hunger and famine was unavoidable, but those that were best-suited to deal with such a situation would survive and pass on their good traits to future generations. 
Darwin could no wait no longer. He took Wallace’s paper and an outline for his book along with some of his previously-unpublished writings and presented them jointly to the Linnean Society in London. A year later, with Wallace still in Malaysia, Origin was finally published. When Wallace eventually found out that his paper had been published without his knowledge, he was happy to have been included with the more-famous Darwin. 
Wallace would return to England in 1862 and finally go to meet Darwin. Some have tried to claim over the year that Darwin stole ideas from Wallace or that there was a conspiracy to deprive Wallace of the credit he was due for his contributions to evolution, but these are without merit. Wallace was to be one of the most loyal defenders of Darwin’s Origin. He wrote Darwinism, which explained and defended the theory of natural selection and became his best-known work. And while today we consider them cofounders of evolution, each had their own approach. For example, Darwin emphasized competition between members of the same species to survive and reproduce, while Wallace emphasized species adaptation as a result of environmental pressures. Throughout Darwin’s life they remain on friendly terms, corresponding and discussing evolution until Darwin’s death in 1882.

Sunday, July 3, 2011


False-color composite of WR104. This composite represents 
eleven shots taken over eight months.
Eight thousand light years from the Earth, in the constellation Sagittarius, lurks a massive binary-star system that is on the verge of becoming a supernova. The star is call Wolf-Rayet 104 and, like Sagittarius the archer, this star could be taking aim at us. If it finds its mark, it could hit us with enough deadly radiation to destroy our protective ozone layer. This would cause drastic climate change that could trigger a mass extinction. 
  Wolf-Rayet stars, named after the two astronomers who  discovered them first, are massive, hot, and very luminous. They are about 25 times more massive than our Sun, and 100,000 times more luminous. Super massive stars like WR-104 live fast and burn their nuclear fuel very quickly, within tens of millions of years. Compare that to the age of our Sun which is 4.6 billion years. As they exhaust their supply of nuclear fuel, they undergo gravitational collapse into a black hole, releasing a massive blast of high-energy radiation—a gamma ray burst so powerful that it would briefly outshine an entire galaxy. Gamma rays are the deadliest, most energetic type of radiation. Energy from the explosion is beamed into two narrow, oppositely directed jets.
  Because WR-104 is a binary star system it produces a spiral-patterned stream of dust and charged particles as the stars orbit each other. As the star collapses, it becomes a dense, flattened, rapidly-rotating disc and the gamma rays are ejected along the rotational axis poles, rushing out like soda from a pop can that had been shaken before opening. If the poles of the collapsing star happen to be pointed at us—look out. And because astronomers can see the spiral of this star full on it means that the star’s rotational axis is pointed in our general direction, as if Sagittarius’s arrow were pointed right at us.
  But don’t worry too much, the time line for such an event is anytime in the next 100,000 years. Also, recent evidence suggests that it is pointing slightly away from us and will miss its mark.