Category: Natural World

Fossils at Pickwick Landing

Paleozoic (250-550 million years ago) fossils.

Along the edge of Pickwick Lake are outcrops of sedimentary rock being slowly broken apart by the action of the waves on the reservoir. We stopped for lunch at Shelter #6 in Pickwick Landing State Park (see map) before finding our cabins for this immersion. Located at the eastern edge of a triangular ridge of land girded by drowned river valleys on two sides the shelter is almost surrounded by water. On a beautiful, clear day at the beginning of spring, with temperatures verging on t-shirt weather, tiny flowers blooming in the grass and tree leaves just sprouting, it was an almost perfect time and place to take a break after a long drive.

Shelter #6.

Yet despite the fact that we were eating later that we normally do, half the class walked right past the shelter and down the rough slope to the lake’s edge. There they found fossils. Beautiful crinoids were weathering out of thin (4cm thick) alternating layers of sandstone and limestone, their long fossilized necks resisting while the limestone around them slowly dissolved away. They also found bivalves partially exposed on the face of the broken cliff and in the small pile of tallus. There were even a few thin sandstone wedges sitting on the rocks at the edge of the water that looked like fossilized burrow molds. It was quite fascinating.

View from inside the shelter.

Neither the word “science” nor the phrase “natural world” was used, and they brought the questions to me, which I always consider better than me asking them. Next year when we study Earth History perhaps the subject will be considered boring when we see it in the classroom, but today, out there on the rocks at the edge of the water, they got a great primer.

This stop, planed solely as a lunch break was so successful that I now wonder if I should plan the immersion trips to introduce the topics we cover in class rather than using them to integrate what we’ve already seen. Let the outdoor experience be the “spark the imagination” part of the lesson. I’m not sure, but it’s something to think about.

[googleMap name=”Picnic Shelter #6, Pickwick Landing State Park” description=”The picnic shelter is located at the point due west of this marker.” width=”480″ height=”400″ mapzoom=”15″ mousewheel=”false”]35.055555, -88.232[/googleMap]

About The Elegant Universe

NOVA’s program The Elegant Universe has an excellent website where the entire three hour video is available for free (with a full screen option). They have also broken the video up into segments and have a great teachers’ page which summarizes what’s in each segment.

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.

Half plant – half animal

The sea slug.

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 in the natural world

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.

Energy inefficiency: Checks and balances

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)

The Energy Star investigation was done by the Government Accountability Office (GAO), which is often tasked with checking up on the other branches of the government. The GAO website is a great information source because they post very readable summaries of their reports, and a highlights page that answers the question, “Why GAO Did This Study” and “What GAO Found”.

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.

Statistical significance

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: Life in Extreme Environments

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.

[googleMap name=”Taylor Glacier” width=”490″ height=”490″ mapzoom=”2″ mousewheel=”false” directions_to=”false”]-77.773, 163.37[/googleMap]

Build your own generator

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.