For the same weight, gasoline delivers 720 times the energy of a bullet.
— Richard A. Mueller, Physics for Future Presidents
When thinking about energy alternatives to fossil fuels, we need to keep in mind how the United States uses its current fuel supplies. Based on a report by the Lawrence Livermore National Laboratory,
28% is used for transportation (gasoline and jet fuel)
40% is used to generate electric power
20% is used for direct heating (natural gas, coal)
32% is used by industry.
(Someone of you will immediately notice that this list adds up to more than 100% — that is because of overlap. For instance, some of the electric power is used by industry.)
The reported numbers vary, but the bottom line is that we use fuel for transportation, electricity, heat and industry in comparable amounts. We need to keep this in mind when discussing energy policies. If we miraculously replace all gasoline with biofuels (alcohol made from plants), we will affect only 28% of the total. So we need to address several “sectors” or uses if we want to significantly reduce fossil fuel emissions.
For those interested in health news blogs, I highly recommend “Health News from NHS.” This science blog looks at the science behind the international news headlines. The unique thing about this blog is its format:
- Summary of news reports
- Where did the story come from?
- What kind of research was this?
- What did the research involve?
- What were the basic results?
- How did the researchers interpret the results?
- Links to Headlines
- Links to Science
Given the long list above, you’ll justifiably conclude that the blog is a little bit longer than the average science news blog. However, you’ll come away with a more thorough understanding of the topic as a result. It may appeal particularly to scientists, but it could appeal to everyone on topics of specific interest.
Freelance writers and editors in the SF Bay Area may want to check out an upcoming 2-day seminar, co-sponsored by Stanford and the American Society of Journalists and Authors. It will cover a range of topics relevant to freelancing in a changing world, including social media, digital media, the future of investigative reporting, grants, fellowships, publishing books, and pitching magazines. Check it out on their website.
A while back I used melatonin supplements in order to help with jet lag, since I was traveling for work to Germany. A friend that travels a lot had recommend melatonin to me, and it did seem to help me re-establish a normal sleep cycle when dealing with a large time shift.
Occasionally I have trouble sleeping through the night at home also. I usually fall asleep right away, but I wake up in the middle of the night and sometimes have trouble falling back to sleep. I have allergies and regularly take antihistamines, so the popular over-the-counter sleep aids like Tylenol PM (which has the same active ingredient as Benadryl as the sleep aid) don’t really work for me. So I wondered if I should take melatonin instead. Although melatonin is an herbal supplement, I did a little research to determine if I think it is safe to take as a normal sleep aid. This is what I found.
Melatonin is a hormone naturally produced by your pineal gland, which is a small pea-sized structure located deep inside your brain between the two hemispheres. Melatonin regulates your circadian rhythm, or basically your 24-hour internal clock. When the sun sets and darkness falls, you begin to naturally secrete increased levels of melatonin. As the melatonin levels rise in your blood, you start to feel sleepier. This hormone level is highest in your blood around bedtime and stays elevated for about 12 hours, then it falls back to the low daytime level around 9 am. Although nighttime melatonin levels remain at least an order of magnitude higher than at daytime throughout your life span, the concentration of melatonin continually decreases as you age. This helps explain why many older adults have problems with frequent insomnia.
Melatonin supplements have been shown to help “reset” the body’s internal clock in those suffering from jet lag, shift workers who work nights and sleep during the day, and blind people. There have been many studies on melatonin use, including studies on its effect to reduce insomnia for older adults. One such research study was performed by Richard Wurtman at the Department of Brain and Cognitive Sciences at MIT. He studied two groups of elderly subjects; one group had frequent insomnia and the other slept normally. Each subject received either a placebo or a melatonin dose about 30 minutes prior to bedtime, and those who received the melatonin were given a dose of either 0.1, 0.3, or 3.0 mg. Each subject was medicated for 7 days, followed by a “washout” period of 7 days. Wurton found that taking the hormone significantly improved the quality of sleep for the older adults. More importantly, he found that they were able to sleep through the night best when taking the 0.3 mg dose. Now perhaps this shouldn’t be surprising, because the body naturally produces melatonin at this “physiological” level. However, the typical over-the-counter melatonin dose is 3 mg and this was determined to be less effective in helping insomnia.
Despite the many studies that have demonstrated melatonin to be an effective sleep aid, there is still controversy about melatonin use though. Some doctors consider it harmless and others potentially harmful. This is true, in part, because the function of the melatonin hormone may not be fully understood. What is understood is that melatonin does more than just regulate the internal clock, such as affecting the onset of puberty. It is also clear that melatonin is only available as a prescription in many European countries and Canada (although this seems to be due more to ingredient regulatory issues than medical concerns), whereas in the US it is an herbal supplement that isn’t regulated by the FDA.
So what does this all mean? Mostly it means that the human body is a complicated system that we don’t entirely understand. But from what I’ve read, I’ve concluded that melatonin is probably a safe and effective sleep aid for adults (at least those over age 50). Of course, I’m a scientist and not a medical doctor. All in all, it is probably best to speak with your physician before taking it regularly as a sleep aid. If you consider taking melatonin, you do need to remember that it is a sleep regulator rather than a sleep inducer. It isn’t the same as taking something like Ambien or Tylenol PM. You also probably want to somehow chop up the over-the-counter pills into smaller pieces (doses) without getting a crumbled mess. For now, I’m just going to stick with daily exercise, relaxing before bedtime, Advil for sore muscles, and the World Finest Ear Plugs for peace and quiet. Sweet dreams.
Let me know….
How much are you willing to pay for residential solar power? Would you rather pay an upfront cost or monthly heating bills?
A square yard of sunlight delivers about a kilowatt when it hits the ground, the same as the average electric power used by a U.S. household
— Physics for Future Presidents, by Richard A. Muller
President Obama has mandated a new energy plan that requires 10% of electricity consumed in the U.S. come from renewable energy sources, such as solar power, by the year 2012. Can we make that goal? Should we with the current technologies?
Just about everyone likes the idea of using solar power to heat and cool their homes. The sun is a potentially clean, free source of energy. What’s not to like about that? We even already have working residential solar power systems on the market. So why isn’t everyone doing it already? Why is only 0.01% of the United State’s electricity generated from solar power? The answer, of course, gets down to cost.
The basic problem is that standard solar cells are expensive and not very efficient. Solar cells are typically 15% efficient. However, the sun is not always out and it is directly overhead only rarely. If you take into account these factors, the average solar cell efficiency is only a few percent. That means that the average solar cell will deliver about 4% of a kilowatt of electric power, if it has an area of 1 square yard. The average household in the U.S. uses about 1 kilowatt of electric power (or 24 kilowatt-hrs per day of energy), which is the equivalent of having 10 100-watt light bulbs turned on. So the average household would need about 25 square yards of solar cells (i.e., 25 sq yds x 0.04 kilowatt/sq yd = 1 kilowatt). Placing this many solar cells on the roof is feasible for many homes, so some people are doing it. It is environmentally clean and politically “green.” Sounds great, right? The problem for most people is the up-front and overall cost.
The price of residential solar power is variable, of course. For the sake of discussion though, I’ll use some 2008 numbers based on California usage (without worrying about issues like tax savings). For a home that uses 1 kilowatt, it costs about $14,000 to have a sufficient residential solar system installed. That means that if you invest $14,000 up-front, you don’t have to pay monthly bills for electricity (except possibly some minor fees for maintenance, but lets ignore those). The amount that an electric power company would charge you for that energy varies, but it averages about 10 cents for 1 kilowatt for 1 hour which translates into $876 per year. If you never have to replace your solar cells, that would mean that you are getting a 6.2% average on your $14,000 investment. Pretty good. The problem is that the solar cells don’t really last forever. To break even, an actuarial calculation shows that the cells would have to last 22 years. If they require repair or replacement sooner than 22 years, which is likely, then you’re actually losing money.
There is some good news though. Currently turning solar power into electricity is expensive, but using the heat directly can be highly efficient without requiring expensive solar cells. As a result, solar-powered water heaters or swimming pool heaters are more popular and economically viable. So you might want to consider those alternatives, if you want to lower your carbon footprint.
Hopefully residential solar heating and cooling will become more attractive in the future, when significantly less expensive and more efficient solar cells have been developed and mass-produced. Stay tuned for future blogs on the science of solar power, since there is a lot of interesting research currently underway.
Nothing in science has any value to society if it is not communicated, and scientists are beginning to learn their social obligations.
— Anne Roe, The Making of a Scientist (1953)
The famous philosophical riddle asks, “If a tree falls in a forest and no one is around to hear it, does it make a sound?” Similarly I pose the riddle, “If a scientist speaks and no one hears, has he said anything?”
Scientists like to focus on what they do best, which is generally doing science. Most scientists are forced to do other things of course, like writing grants to get funding or presenting their research results at professional conferences, and they can live with that. But most scientists that I know do not want to hassle with “marketing” their science. Some have the perhaps naive belief that remarkable science will sell itself, and others feel that this is best left to the marketing experts. Although both beliefs certainly have validity, I think scientists still need to have basic Web 2.0 skills so they can directly communicate their science to the world.
But who has the time? If you are like many scientists, then you probably have a personal Facebook account that you use regularly, as well as a professional Linked In account that you rarely update. That is about it. If you think that probably isn’t enough, then I have a book recommendation for you. Your probably thinking, “Read a marketing book? Are you serious?” But really, trust me, you don’t have to invest a lot of time and it won’t even put you to sleep.
In order to help expand my social media skills, I recently read the book“Inbound Marketing: Get Found Using Google, Social Media, and Blogs” by Brian Halligan and Dharmesh Shah. The book is written as a basic primer for clueless small businessmen to learn how to connect to today’s buyers online. As you read each short chapter, the authors take you through each concept with a practical hands-on style using examples of small businesses that have successfully applied these inbound marketing tools. The most remarkable thing about the book is that it is easy to read. The conversational writing style makes it seem like your best friend is a Web 2.0 expert, and he is chatting with you over your laptop as you sip a glass of wine in the dining room.