science – Page 21 – Montessori Muddle

How science works

Artist's impression of the Big Bang. By cédric sorel: http://commons.wikimedia.org/wiki/File:Big_bang.jpg

Science progresses from failure. When experiments don’t work, we often learn more from why they did not work than if they had given us the results we expected. Frequently, it is how scientists deal with this adversity that results in advances in science.

We build models of the world, but by definition these models are incomplete. They are only metaphors for the actual world. When our models fail, we learn, and we expand our models.

Arno Penzias and Robert Wilson won the Noble Prize for Physics for discovering the background noise left by the Big Bang. They only did so after spending a year trying to figure out why their radio telescope kept giving them too much static for them to use for their intended purpose (to map the universe’s bright stars).

Evolution and drug resistant bacteria

Superbugs. When the environment changes, those fortunate organisms who are better adapted to the new environment will live longer and produce more offspring than those that are poorly adapted. (The Chrysalids, is a great book that encapsulates this principle in a powerful coming-of-age story.)

When it comes to bacteria, some small fraction of any strain of bacteria infecting you are, because of random genetic mixing, more resistant to the antibiotics you may be taking. This is why your doctor often makes you to take the antibiotic for a few days after the symptoms are gone; to kill those last most resistant bacteria cells.

Unfortunately, not everyone takes the full course of antibiotics, and some bacteria cells are extremely drug resistant. Over the years since the discovery of penicillin about a century ago, bacterial cells resistant to penicillin have been surviving and reproducing, so that there are now strains of bacteria that are resistant to the drug.

Fortunately drug researchers are developing new antibiotics all the time. When your doctor prescribes one antibiotic and it doesn’t work, they can usually prescribe another that will work because a bacteria strain that has an immunity to one drug might not have an immunity to another, especially if the other is a very different type of drug.

Unfortunately, some bacterial strains have developed that are resistant to a lot of different types of drugs (according to the World Health Organization), and these bacteria are responsible for thousands of deaths in hospitals around the world each year.

Norway has come up with one promising solution; don’t use as many antibiotics. Instead of treating every, or even most colds with antibiotics, their doctors take a wait and see attitude. They prescribe other medicines that reduce the symptoms, the coughing and runny nose, and let the body’s immune system deal with the bacterial infection. And it is working. In Norway, they are able to use penicillin varieties that would not be effective in other countries.

Without the overuse of antibiotics, drug-resistant strains of bacteria are not as competitive as other strains that commonly infect people. Without antibiotic overuse the superbugs aren’t so super after all. So, using less antibiotics means fewer infections with drug-resistant strains.

It’s a bit as if, somewhere in the forests of India, one tiger was born that was much, much better at hiding from and attacking people than the ordinary tiger, but it was smaller than other tigers. Ordinarily, this “supertiger” and its genes would probably die out because it would not be able to compete with the other tigers to reproduce. However, when people start hunting tigers, the supertiger survives better and passes on its genes. Now we have alot more supertigers and a lot more people are being attacked. All because people started killing the tigers.

Evolution is a fascinating process with such a multitude of complicated interactions. I also recommend that students read the introduction to the Origin of Species. It is truly an example of beautiful science. The language is challenging but, I think, worth it.

Experiments in cooking: Testing for pectin

Ribes_rubrum2005-07-17 — Ribes rubrum. From Wikipedia.

Cooking is chemistry writ large. You start by learning how to measure volumes, mass and ratios, but end up talking about polymers and stoichiometry. It can get very complicated, but it’s easy enough that anyone can do it, going into different depths.

I’m planning on jam making this fall and in testing a recipe I became curious about if I could do it without adding store-bought pectin. Red currants should have enough pectin but the question of extracting it came up.

I was curious to see if I actually get more pectin from the liquid squeezed last through the handkerchief (with much wringing) than I get from the pulp and juice of the red currants I initially squeezed through a coarse strainer. So, I tested the two batches of liquid for pectin. A simple application of science in cooking.

Date: 12/29/09.

Hypothesis: The juice (the filtrate) squeezed out of the currants through the strainer will have less pectin than the juice strained out of the seed and skin leftover of the straining (the retentate) because I think I remember reading somewhere (always dangerous) that pectin can be found in or just beneath the surface of the skin of fruits.

Procedure: Using the test from the University of Minnesota extension service: Add 1 teaspoon of juice to 1 tablespoon of rubbing alcohol and observe how well it coagulates after 2 minutes. This test is performed in two small shot glasses.

Observations: It is difficult to quantify how firm are the gels that forms at the bottom of the shot glasses. Although I could construct a simple device to test gels resistance for force, I opt to assess the gels by swirling the glasses and observing how they move. Eyeballing the results, it seems that the first extraction of pulp and juice has more pectin. An independent observer agrees with this observation.

Conclusion: My initial hypothesis is wrong. Based on this experiment I now hypothesize that the pulp of the currants has more pectin. Five minutes of internet searching seems to confirm this new hypothesis, and suggests that my initial belief that pectin can be found under the skin of fruits comes from the fact that this is true for citrus fruits.

Why collaboration is important

Montessori middle schools depend a lot on collaborative work and discussions. Individual parts of group work allow students to specialize in areas, hopefully, where they are interested and willing to learn the most. Then when they share their work with the group the whole group gets the information, and the person presenting it gets feedback from different perspectives. Collaborative work is excellent preparation for creative work in the future.

Some recent research by Kevin Dunbar, a neuroscience at the University of Toronto, gives some strong support to the usefulness of collaborative work. He found that group discussions, with people from different backgrounds can be much more effective at solving problems than discussions among specialists. Different backgrounds mean that each person is forced to take a step back from their expertise and think and describe the problem in a way someone else with a different perspective can understand. This allows both the expert and the person they are describing the problem to, to see the problem from different perspectives.

The universe … for scale

The American Natural History Museum has a YouTube channel with some interesting science-related videos. The one above, “shows the known universe as mapped through astronomical observations.”

Every satellite, moon, planet, star and galaxy is represented to scale and in its correct, measured location according to the best scientific research to-date.

Human? nature

To follow up on the previous post on the evolutionary benefits of kindness, this essay by Marc Hauser describes some of the science that indicates that morality is innate. Not religious affiliation, gender, nationality nor political views affect how people respond to moral dilemmas.

“We tend to see actions as worse than omissions of actions.” People tend to believe that deliberately hurting a healthy person to save one or more others is morally repugnant if the others would only be hurt by your inaction.

The evolutionary benefits of kindness

Evolution is often summed up in the phrase, “survival of the fittest”, well sometimes “fittest” can also refer to kindness. Having empathy is evolutionarily beneficial. As individuals, the more we give to others the more respect we gain for ourselves. As a group or a society, when people are able to cooperate they do better than when they cannot. What scientists have recently been uncovering is that empathy and the urge to cooperate are built into our very genes.

This research ties in elegantly with Montessori philosophy. The benefits of kindness and cooperation seem obvious when you think about it, but the fact that we are genetically predisposed to act in this way helps explain why the emphasis on cooperative work works so well in early childhood classrooms.

If you put this research together with the way society is currently evolving, where problems have to be dealt with with teams from different backgrounds, perspectives and disciplines, it really points out the importance of collaborative work in the middle school.