Posts about why
animals appropriate technology bacteria biology Career Cats cool curiouscat economy Energy Engineering engineering education engineers evolution experiment food fun Funding government green Health Care human health innovation K-12 kids Life Science medical research nature ocean physics Products Research Robots Science science education science explained science facts science webcasts scientific inquiry Students Technology university research USA water webcasts

Scientific Inquiry Leads to Using Fluoride for Healthy Teeth

Posted on April 18, 2015  Comments (0)

This webcast, from the wonderful SciShow, explores how we discovered fluoride helps prevent tooth decay and how we then used that knowledge and finally discovered why it worked.

I love stories of how we learn for observing what is happening. We don’t always need to innovate by thinking up creative new ideas. If we are observant we can pick up anomalies and then examine the situation to find possible explanations and then experiment to see if those explanations prove true.

When working this way we often are seeing correlation and then trying to figure out which part of the correlation is an actual cause. So in this dental example, a dentist noticed his patients had bad brown stains on their teeth than others populations did.

After investigation the natural fluoridation of the water in Colorado Springs, Colorado, USA seemed like it might be an explanation (though they didn’t understand the chemistry that would cause that result). They also explored the sense that the discolored teeth were resistant to decay.

Even without knowing why it is possible to test if the conditions are the cause. Scientists discovered by reducing the level of fluoridation in the water the ugly brown stains could be eliminated (these stains took a long time to develop and didn’t develop in adults). Eventually scientists ran an experiment in Grand Rapids, Michigan and found fluoridation of the water achieved amazing results for dental health. The practice of fluoridation was then adopted widely and resulted in greatly improved dental health.

In 1901, Frederick McKay, a recent dental school graduate, opened a dental practice in Colorado Springs, Colorado. He was interested in what he saw and sought out other dentists to explore the situation with him but had little success. In 1909, he found some success when renowned dental researcher Dr. G.V. Black collaborate with him.
Dr. H. Trendley Dean, head of the Dental Hygiene Unit at the National Institute of Health built on their work when he began investigating the epidemiology of fluorosis in 1931. It wasn’t until 1945 that the Grand Rapids test started. Science can take a long time to move forward.

Only later did scientists unravel why this worked. The fluoride reacts to create a stronger enamel than if the fluoride is not present. Which results in the enamal being less easily dissolved by bacteria.
Health tip: use a dental stimudent (dental picks) or floss your teeth to maintain healthy gums and prevent tooth decay. It makes a big difference.

Related: Why does orange juice taste so bad after brushing your teeth? – Microbiologist Develops Mouthwash That Targets Only Harmful Cavity Causing Bacteria – Using Nanocomposites to Improve Dental Filling Performance – Finding a Dentist in Chiang Mai, Thailand – False Teeth For Cats – Why Does Hair Turn Grey as We Age?

Can You Effectively Burn Calories by Drinking Cold Water?

Posted on April 15, 2013  Comments (1)

Neil deGrasse Tyson stated on Twitter:

Wanna lose 1200 Calories a month? Drink a liter of ice water a day. You burn the energy just raising the water to body temp.

What if your body is trying to cool down? I would imagine we have to use energy to cool off (though I am no expert on this)? So if you drink cold water and your body has less need to cool off, couldn’t this actually end up “saving” your body needing to burn calories – and thus cause yourself to gain weight?

This model would be similar to a server room that was cooled with air conditioning and cold winter air to cool off the servers. If there was less cold air used then more electricity would be used running the air conditioner to cool down the servers. I don’t know if it is a decent analogy though – maybe that isn’t an usable model for how we cool off.

I know we cool off partially by pushing water out onto the exterior of our skin to have it evaporate and cool us off. I would think that takes energy to do.

I do get that it takes energy to raise the temperature of the water you consume. It does make sense to me that if you were cold (like say I was during the winter living in the house I grew up in) you would use energy raising the temperature of the water.

What the overall energy situation is if your body needs to cool down seems questionable to me. Please let me know your thoughts. In any event his statement is accurate. It is just that the implication may lead people astray; that you can consume 1,200 Calories extra to balance the 1,200 Calories drinking cold water uses (or loss weight by having reduced your excess Calories by 1,200 if you eat exactly the same things you would without the cold water).

Related: Why is it Colder at Higher Elevations? – Does Diet Soda Result in Weight Gain? – Why Does Hair Turn Grey as We Age? – How Corn Syrup Might Be Making Us Fat – Why Wasn’t the Earth Covered in Ice 4 Billion Years Ago (When the Sun was Dimmer)

Why is the Sky Dark at Night?

Posted on October 11, 2012  Comments (8)

The answer isn’t quite as simple as it seems. I find the wording in the video a bit confusing.

The point I believe, is that the sky is dark instead of light. But not that the brightness would be huge (so for example, you couldn’t necessarily read my book outside just by starlight). The light would be very faint, it is just that it would be lightish instead of blackish, due to the reasons explained (redshift etc.). At least that is my understanding.

Related: Why is it Colder at Higher Elevations? – Why Does the Moon Appear Larger on the Horizon? – Why is the Sky Blue? – Why Wasn’t the Earth Covered in Ice 4 Billion Years Ago – When the Sun was Dimmer

The Appendix Serves As a Reservoir of Beneficial Bacteria

Posted on July 8, 2012  Comments (0)

This is an interesting explanation for the purpose of the appendix.

The appendix does have a use – re-booting the gut

The US scientists found that the appendix acted as a “good safe house” for bacteria essential for healthy digestion, in effect re-booting the digestive system after the host has contracted diseases such as amoebic dysentery or cholera, which kill off helpful germs and purge the gut.

This function has been made obsolete by modern, industrialised society; populations are now so dense that people pick up essential bacteria from each other, allowing gut organisms to regrow without help from the appendix, the researchers said.

But in earlier centuries, when vast tracts of land were more sparsely populated and whole regions could be wiped out by an epidemic of cholera, the appendix provided survivors with a vital individual stockpile of suitable bacteria.

Related: Microbes Flourish In Healthy People – Beneficial Bacteria – Foreign Cells Outnumber Human Cells in Our Bodies

Why Does the Moon Appear Larger on the Horizon?

Posted on May 16, 2010  Comments (0)

Why does the Moon look so huge on the horizon?

If you’ve ever seen the Moon rising over the horizon, looking so fat and looming that you felt like you could fall right into it, then you’ve been a victim of the famous Moon Illusion. And it is an illusion, a pervasive and persuasive one.
…
When the Moon is on the horizon, your brain thinks it’s far away, much farther than when it’s overhead. So the Ponzo Illusion kicks in: your brain sees the Moon as being huge, and it looks like you could fall into it. The Illusion works for the Sun, too. In fact, years ago I saw Orion rising over a parking lot, and it looked like it was spread across half the sky. It’s an incredibly powerful illusion.

Oddly enough, when it’s on the horizon, the Moon actually is farther away than when it’s overhead. Not by much, really, just a few thousand kilometers (compared to the Moon’s overall distance of about 400,000 kilometers).
…
So the Moon Illusion is just that. It’s not the air acting like a lens, or foreground objects making it look big by comparison. It’s just the way we see the shape of the sky together with the well-known Ponzo Illusion.
..
Science taking something we perceive as real, breaking it down, and showing it to be an interesting but decidedly unreal illusion? Well, that’s what science does! It helps us not only understand the world better, but it also makes the world cooler, too.

Related: Why People Often Get Sicker When They’re Stressed – Why is it Colder at Higher Elevations? – Albert Einstein, Marylin Monroe Hybrid Image – Answers to Why? – Bigger Impact: 15 to 18 mpg or 50 to 100 mpg?

Bee Colonies Continue to Collapse

Posted on May 3, 2010  Comments (2)

The activity to find the causes of Colony Collapse Disorder provides a view into the scientific inquiry process of complex living systems. Finding answers is not easy.

Fears for crops as shock figures from America show scale of bee catastrophe

Disturbing evidence that honeybees are in terminal decline has emerged from the United States where, for the fourth year in a row, more than a third of colonies have failed to survive the winter.

The decline of the country’s estimated 2.4 million beehives began in 2006, when a phenomenon dubbed colony collapse disorder (CCD) led to the disappearance of hundreds of thousands of colonies. Since then more than three million colonies in the US and billions of honeybees worldwide have died and scientists are no nearer to knowing what is causing the catastrophic fall in numbers.
…
It is estimated that a third of everything we eat depends upon honeybee pollination.
…
Potential causes range from parasites, such as the bloodsucking varroa mite, to viral and bacterial infections, pesticides and poor nutrition stemming from intensive farming methods.
…
“We believe that some subtle interactions between nutrition, pesticide exposure and other stressors are converging to kill colonies,” said Jeffery Pettis, of the ARS’s bee research laboratory.
…
“It’s getting worse,” he said. “The AIA survey doesn’t give you the full picture because it is only measuring losses through the winter. In the summer the bees are exposed to lots of pesticides. Farmers mix them together and no one has any idea what the effects might be.” Pettis agreed that losses in some commercial operations are running at 50% or greater.

High Levels of Miticides and Agrochemicals in North American Apiaries: Implications for Honey Bee Health (open access paper on the topic, March 2010)

The 98 pesticides and metabolites detected in mixtures up to 214 ppm in bee pollen alone represents a remarkably high level for toxicants in the brood and adult food of this primary pollinator. This represents over half of the maximum individual pesticide incidences ever reported for apiaries. While exposure to many of these neurotoxicants elicits acute and sublethal reductions in honey bee fitness, the effects of these materials in combinations and their direct association with CCD or declining bee health remains to be determined.

Related: Solving the Mystery of the Vanishing Bees – Virus Found to be One Likely Factor in Bee Colony Colapse Disorder – Bye Bye Bees

Why Wasn’t the Earth Covered in Ice 4 Billion Years Ago – When the Sun was Dimmer

Posted on April 2, 2010  Comments (2)

Climate scientists from all over the globe are now able to test their climate models under extreme conditions thanks to Professor Minik Rosing, University of Copenhagen. Rosing has solved one of the great mysteries and paradoxes of our geological past, namely, “Why the earth’s surface was not just one big lump of ice four billion years ago when the Sun’s radiation was much weaker than it is today.” Until now, scientists have presumed that the earth’s atmosphere back then consisted of 30% carbon dioxide (CO2) which ensconced the planet in a protective membrane, thereby trapping heat like a greenhouse.

The faint early sun paradox
In 1972, the late, world famous astronomer Carl Sagan and his colleague George Mullen formulated “The faint early sun paradox. ” The paradox consisted in that the earth’s climate has been fairly constant during almost four of the four and a half billion years that the planet has been in existence, and this despite the fact that radiation from the sun has increased by 25-30 percent.

The paradoxical question that arose for scientists in this connection was why the earth’s surface at its fragile beginning was not covered by ice, seeing that the sun’s rays were much fainter than they are today. Science found one probable answer in 1993, which was proffered by the American atmospheric scientist, Jim Kasting. He performed theoretical calculations that showed that 30% of the earth’s atmosphere four billion years ago consisted of CO2. This in turn entailed that the large amount of greenhouse gases layered themselves as a protective greenhouse around the planet, thereby preventing the oceans from freezing over.

Mystery solved
Now, however, Professor Minik Rosing, from the Natural History Museum of Denmark, and Christian Bjerrum, from the Department of Geography and Geology at University of Copenhagen, together with American colleagues from Stanford University in California have discovered the reason for “the missing ice age” back then, thereby solving the sun paradox, which has haunted scientific circles for more than forty years.

Professor Minik Rosing explains, “What prevented an ice age back then was not high CO2 concentration in the atmosphere, but the fact that the cloud layer was much thinner than it is today. In addition to this, the earth’s surface was covered by water. This meant that the sun’s rays could warm the oceans unobstructed, which in turn could layer the heat, thereby preventing the earth’s watery surface from freezing into ice. The reason for the lack of clouds back in earth’s childhood can be explained by the process by which clouds form. This process requires chemical substances that are produced by algae and plants, which did not exist at the time. These chemical processes would have been able to form a dense layer of clouds, which in turn would have reflected the sun’s rays, throwing them back into the cosmos and thereby preventing the warming of earth’s oceans. Scientists have formerly used the relationship between the radiation from the sun and earth’s surface temperature to calculate that earth ought to have been in a deep freeze during three billion of its four and a half billion years of existence. Sagan and Mullen brought attention to the paradox between these theoretical calculations and geological reality by the fact that the oceans had not frozen. This paradox of having a faint sun and ice-free oceans has now been solved.”

CO2 history iluminated
Minik Rosing and his team have by analyzing samples of 3.8-billion-year-old mountain rock from the world’s oldest bedrock, Isua, in western Greenland, solved the “paradox”.

But more importantly, the analyses also provided a finding for a highly important issue in today’s climate research – and climate debate, not least: whether the atmosphere’s CO2 concentration throughout earth’s history has fluctuated strongly or been fairly stable over the course of billions of years.

“The analyses of the CO2-content in the atmosphere, which can be deduced from the age-old Isua rock, show that the atmosphere at the time contained a maximum of one part per thousand of this greenhouse gas. This was three to four times more than the atmosphere’s CO2-content today. However, not anywhere in the range of the of the 30 percent share in early earth history, which has hitherto been the theoretical calculation. Hence we may conclude that the atmosphere’s CO2-content has not changed substantially through the billions of years of earth’s geological history. However, today the graph is turning upward. Not least due to the emissions from fossil fuels used by humans. Therefore it is vital to determine the geological and atmospheric premises for the prehistoric past in order to understand the present, not to mention the future, in what pertains to the design of climate models and calculations,” underscores Minik Rosing.

Full press release from the University of Copenhagen in Denmark.

Related: Sun Missing It’s Spots – Solar Storms – Why is it Colder at Higher Elevations? – Magnetic Portals Connect Sun and Earth

What is a Molecule?

Posted on August 24, 2009  Comments (4)

One of the things I keep meaning to do more of with this blog is provide some post on basic science concepts that may help raise scientific literacy. Some of these will be pretty obvious but even reminders on some facts you know can sometimes help.

What is a molecule?

A molecule is the smallest particle of a compound that has all the chemical properties of that compound. Molecules are made up of two or more atoms, either of the same element or of two or more different elements. The example of molecules are water (H2O) and carbon dioxide (CO2) and molecular nitrogen (N2).

Organic molecules contain Carbon, for example, Methane CH4). The original definition of “organic” chemistry came from the misconception that organic compounds were always related to life processes.

A few types of compounds such as carbonates, simple oxides of carbon and cyanides, as well as the allotropes of carbon, are considered inorganic. The division between “organic” and “inorganic” carbon compounds while “useful in organizing the vast subject of chemistry…is somewhat arbitrary”

Ionic compounds, such as common salt, are made up not of molecules, but of ions arranged in a crystalline structure. Unlike ions, molecules carry no net electrical charge.

Related: Why is it Colder at Higher Elevations? – Why is the Sky Blue? – 10 Science Facts You Should Know – Bacteria Communicate Using a Chemical Language

Why People Often Get Sicker When They’re Stressed

Posted on March 21, 2009  Comments (5)

Researchers at UT Southwestern Medical Center identified a receptor, known as QseE, which resides in a diarrhea-causing strain of E coli. The receptor senses stress cues from the bacterium’s host and helps the pathogen make the host ill. A receptor is a molecule on the surface of a cell that docks with other molecules, often signaling the cell to carry out a specific function.

Dr. Vanessa Sperandio, associate professor of microbiology at UT Southwestern and the study’’ senior author, said QseE is an important player in disease development because the stress cues it senses from a host, chiefly epinephrine and phosphate, are generally associated with blood poisoning, or sepsis.

“Patients with high levels of phosphate in the intestine have a much higher probability of developing sepsis due to systemic infection by intestinal bacteria,” Dr. Sperandio said. “If we can find out how bacteria sense these cues, then we can try to interfere in the process and prevent infection.”

Millions of potentially harmful bacteria exist in the human body, awaiting a signal from their host that it’s time to release their toxins. Without those signals, the bacteria pass through the digestive tract without infecting cells. What hasn’t been identified is how to prevent the release of those toxins.

“There’s obviously a lot of chemical signaling between host and bacteria going on, and we have very little information about which bacteria receptors recognize the host and vice versa,” Dr. Sperandio said. “We’re scratching at the tip of the iceberg on our knowledge of this.”

“When people are stressed they have more epinephrine and norepinephrine being released. Both of these human hormones activate the receptors QseC and QseE, which in turn trigger virulence. Hence, if you are stressed, you activate bacterial virulence.” Dr. Sperandio said the findings also suggest that there may be more going on at the genetic level in stress-induced illness than previously thought.

“The problem may not only be that the stress signals are weakening your immune system, but that you’re also priming some pathogens at the same time,” she said. “Then it’s a double-edged sword. You have a weakened immune system and pathogens exploiting it.”

Previous research by Dr. Sperandio found that phentolamine, an alpha blocker drug used to treat hypertension, and a new drug called LED209 prevent QseC from expressing its virulence genes in cells. Next she will test whether phentolamine has the same effect on QseE.

Full press release: Researchers probe mechanisms of infection

Related: posts on the scientific method in action – How Cells Age – Why ‘Licking Your Wounds’ Works – Waste from Gut Bacteria Helps Host Control Weight

Why Does Hair Turn Grey as We Age?

Posted on February 26, 2009  Comments (8)

A team of European scientists have learned why our hair turns gray as we age. Despite the notion that gray hair is a sign of wisdom, these researchers show that going gray is caused by a massive build up of hydrogen peroxide due to wear and tear of our hair follicles. The peroxide winds up blocking the normal synthesis of melanin, our hair’s natural pigment.

“Not only blondes change their hair color with hydrogen peroxide,” said Gerald Weissmann, MD, Editor-in-Chief of The FASEB Journal. “All of our hair cells make a tiny bit of hydrogen peroxide, but as we get older, this little bit becomes a lot. We bleach our hair pigment from within, and our hair turns gray and then white. This research, however, is an important first step to get at the root of the problem, so to speak.”

The researchers made this discovery by examining cell cultures of human hair follicles. They found that the build up of hydrogen peroxide was caused by a reduction of an enzyme that breaks up hydrogen peroxide into water and oxygen (catalase). They also discovered that hair follicles could not repair the damage caused by the hydrogen peroxide because of low levels of enzymes that normally serve this function (MSR A and B). Further complicating matters, the high levels of hydrogen peroxide and low levels of MSR A and B, disrupt the formation of an enzyme (tyrosinase) that leads to the production of melanin in hair follicles. Melanin is the pigment responsible for hair color, skin color, and eye color. The researchers speculate that a similar breakdown in the skin could be the root cause of vitiligo.

Weissmann added. “This study is a prime example of how basic research in biology can benefit us in ways never imagined.”

See full press release

Related: The Chemistry of Hair Coloring – Students Create “Disappearing” Nail Polish – Common Ancestor 6-10,000 Years Ago For All Blue-eyed People – posts with scientific explanations for the world we live in

Learning About the Moon

Posted on December 30, 2008  Comments (2)

Planetary scientist Jennifer Heldmann discusses the Moon. From Fora.tv which has a wide selection of great webcasts.

Related: Science and Engineering Webcast Directory – China Reaches for the Moon – Astronomers Find a Planet Denser Than Lead – Studying Martian Soil for Evidence of Microbial Life – Cool Astronaut photo