The Elegant Universe's Teachers' page is excellent.
Created in 2003, when string theory was making it’s big splash in the popular consciousness, The Elegant Universe starts with Newton’s observations of gravity, shows Einstein’s separate explanations of why gravity works and the nature of the sub-atomic world, and finally delves into string theory which tries to reconcile Einstein’s two theories into a unified whole.
We don’t usually get past Newton in middle school, but this PBS program introduces such a wider and weirder view of the universe that it can help strike the imagination. It also presents complex concepts in an intelligible way.
Next year we’ll be going into the differences between plant and animal cells, as well as into the differences between plants and animals. There are a number of fundamental differences, starting with the fact that plants can photosynthesize to convert sunlight directly into energy and animals can’t. Except for the sea slug. Sea slugs have found a way to pirate chloroplasts from green algae (found via Immersion Blog).
Chloroplasts are the green cellular bodies (organelles) that perform photosynthesis. The species Elysia chlorotica eats the algae when they are young and instead of digesting them entirely, keep the chloroplasts in their gut.
Young E. chlorotica fed with algae for two weeks, could survive for the rest of their year-long lives without eating – Brahic, 2008
What’s even more intriguing is that there is evidence that the sea slugs have incorporated parts of the algae into their own DNA so they can maintain the right conditions for the chloroplasts to survive in the new host (Rumpho et al., 2008). The Sea Slug Form has a nice page on other solar-powered slugs.
Mathematics is the language of science. Scientists refine and refine their observations of the complexity of the natural world and try to boil these complex observations down to simple relationships, relationships that are expressed in mathematics. This, I think, is part of the human condition. Our brains are designed to extract simple relationships, heuristics, rules of thumb, from the observations of our senses. It is why Einstein’s equation, E=mc2, has captivated our imagination for so long, why physicists struggle to find the unified theory, and why fractals are so fascinating.
Cristóbal Vila’s short video (found via The Daily Dish) captures some of the magic of the relationship between mathematics and the world.
The government’s Energy Star program to label products that are more energy efficient was in the news recently (and there are a lot of different products that have the label). The New York Times ran a story on how auditors, when asked by congress, submitted 20 fake and often ridiculous products to be approved for the stickers many environmentally aware people look for when they buy appliances like refrigerators (an AP report is also available).
GAO obtained Energy Star certifications for 15 bogus products, including a gas-powered alarm clock. – (GAO, 2010)
This Energy Star poster now takes a somewhat sinister (Orwellian) cast.
This study highlights the lesson that while we want to be environmentally aware, we must always remain skeptical of claims pushed by manufacturers, even if they are supported by government certification. It also highlights an excellent application of the concept of checks and balances. One branch of government (congress) checks up on others (EPA and DOE who run the Energy Star program are part of the executive branch) and the others are forced to improve.
Normal distribution with 95% unshaded. Adapted from Wikimedia Commons.
A discussion of statistical significance is probably a bit above middle school level, but I’m posting a note here because it is a reminder about the importance of statistics. In fact, students will hear about confidence intervals when they hear about the margin of error of polls in the news and the “significant” benefits of new drugs. Indeed, if you think about it, the development of formal thinking skills during adolescence should make it easier for students to see the world from a more probabilistic perspective, noticing the shades of grey that surround issues, rather that the more black and white, deterministic, point of view young idealists tend to have. At any rate, statistics are important in life but, according to a Science Magazine article, many scientists are not using them correctly.
One key error is in understanding the term “statistically significant”. When Ronald A. Fisher came up with the concept he arbitrarily chose 95% as the cutoff to test if an experiment worked. The arbitrariness is one part of the problem, 95% still means there is one chance in twenty that the experiment failed and with all the scientists conducting experiments, that’s a lot of unrecognized failed experiments.
But the big problem is the fact that people conflate statistical significance and actual significance. Just because there is a statistically significant correlation between eating apples and acne, does not mean that it’s actually important. It could be that this result predicts that one person in ten million will get acne from eating apples, but is that enough reason to stop eating apples?
It is a fascinating article that deals with a number of other erroneous uses of statistics, but I’ve just spent more time on this post than I’d planned (it was supposed to be a short note). So I’d be willing to bet that there is a statistically significant correlation between my interest in an issue and the length of the post (and no correlation with the amount of time I intended to spend on the post).
Blood Falls, Antarctica. Note the tent in the lower left for scale. From the U.S. Antarctic Program.
For millions of years, cut off from the atmosphere and the sun by an immense continental glacier, microbes survived in a lake of salty water under the ice. No air and no sunlight means no oxygen, so the water became anoxic and able to dissolve iron out of the rocks and sediment beneath the lake. But sometimes the lake breaches and the iron rich water comes to the surface where it is exposed to the air once again and the iron reacts with the oxygen to form a red mineral, hematite (rust). A template for life on Europa? Maybe. Blood Falls, Antarctica.
If you don’t have a generator building kit, but do have a few magnets, some wire and a long nail, you can build your own generator using the instructions on William Beaty’s website, ‘Ultra-simple Electric Generator‘. The video gives excellent, detailed instructions, but there are also written instructions with a supplies list.
UPDATE: A small group of my students tried this and, despite the complaints, I thought it was a useful exercise. I’m looking forward to their presentation tomorrow.
I remain fascinated by the Brazilian study that found that kids living in homes without electricity did not have the same sleep deprivation issues as those with electricity. I thought of it again recently when I ran across the term “nature-deficit disorder” in Oak Hill Montessori school’s newsletter.
Unstructured nature time is so important because children live through their senses. When they are right there in the forest, they are getting a primary multi-sensory experience of nature as opposed to the secondary, often distorted, dual-sensory view presented by TV. – Daniels, 2009 (p. 4)
The idea of nature-deficit disorder comes from the book “Last Child in the Woods” by Richard Louv. Written in 2005 and updated in 2008 with a bunch of practical things you can do to change things, Louv’s book advocates for more time in nature because, “a growing body of research links our mental, physical, and spiritual health directly to our association with nature.” Not only does it affect our individual health, but directly experiencing nature also helps increase environmental awareness (which ties into the Montessori peace curriculum). Louv argues that children have a fundamental right to walk in the woods:
Science sheds light on the measurable consequences of introducing children to nature; studies pointing to health and cognition benefits are immediate and concrete. We also need to articulate the underlying “first principle”—one that emerges not only from what science can prove, but also from what it cannot fully reveal; one that resists codification because it is so elemental: a meaningful connection to the natural world is fundamental to our survival and spirit, as individuals and as a species. Louv (2009)
I can’t say I disagree very much with this diagnosis. My adolescents are too often opting for technology rather than being outside, especially if it’s in nature. This is one reason my students are building the nature trail. The trail has been coming along slowly though, but the seasons are changing and we’ll spend more time outside in the warmer weather. The timing is also nice because we’ve just finished covering simple machines in physics. There are logs and junk to be moved and saplings to be cleared.
Note: Louv has a long list of links to print and broadcast articles on the whole “nature-deficit disorder” concept.
