Middle and High School … from a Montessori Point of View
Charles Darwin and colleagues attempted to vegetate the barren, volcanic Ascension Island with plants from botanical gardens around the world. Essentially, it was an experiment in transforming. And it worked. Howard Falcon-Lang has the details at the BBC.
This year, I’ve been basing my introduction to basic chemistry for my middle school students around the periodic table of the elements. The first step, however, is to teach them how to draw basic models of atoms.
I started it off by having the students memorize the first 20 elements (H through Ca), in their correct order — by atomic number — over their winter break.
So that they’d have a bit of context, I went over the basic parts of an atom (protons, neutrons, and electrons) and made it clear that the name of the element is determined solely by the number of protons. I even had them draw a few atoms with the protons and neutrons in the center and the electrons in shells. Since I’d dumped all of this on them in a single class period, it probably was a bit much, but since it was just to give them some context I did not expect the 7th graders, who had not seen this before, to remember it all; for the 8th graders it should have been just a review.
Most students did a good job at the memorization. Some found songs on the the internet that helped, while others just pushed through. Having the two weeks of winter break to work on it probably helped too.
When we got back to school, the first thing I did was give them an outline of the upper part of the periodic table and asked them to fill it in with the element names.
After they’d filled out their periodic table template, I went into the parts of the atoms in more detail, and had them practice. The key points I wanted them to remember were:
The atomic number is the number of protons. Since they memorized the elements in order, they should be able to figure this out on their own — but they could also look it up quickly on the periodic table, or look at the element symbol where the atomic number is sometimes written on the lower left.
The small atoms that we’re looking at tend to have the same number of neutrons as protons, but that’s not necessarily the case. So how do you know how many neutrons? You have to ask, or look at the atomic mass number, which is usually written to the upper left of the atom. Since the atomic mass is the sum of the number of protons and neutrons, if you know the atomic mass and the number of protons, you can easily figure out the number of neutrons. (Note that electrons don’t contribute to the mass of the atom because their masses are so much smaller than the masses of neutrons and protons.
Electron Shells: Electrons orbit around the nucleus in a series of shells. Each shell can hold a certain maximum number of electrons (2 for the first shell; 8 for the second shell; and 8 for the third). And to draw the atoms you fill up the inner shells first then move on to the outer shells.
So, if I wrote just the element symbol and its atomic mass on the board that students should be able to figure out the number of particles.
For example, the most common form (isotope) of carbon-12 is written as:
Carbon-14 is the radioactive isotope of carbon that is often used in carbon dating of historical artifacts. It is written as:
The only difference between carbon-12 and carbon-14 is that the latter has two more neutrons. These are therefore two isotopes of carbon.
Note: A picture of a hydrogen atom can be found here.
Update: I’ve created an interactive app that will draw atoms (of the first 20 elements), to go with a worksheet for student practice.
This curious video advocates for a new type of nuclear reactor (that runs on thorium) over traditional uranium reactors and chemical fuels. In doing so it gives a useful, but quick, explanation of how energy is produced from these sources.
Dr. Austin has the middle school students build physical models of the continents as an exercise in geography. They use some type of cellulose clay to shape the topography then paint on or apply other icons to represent other types of spatial data; one group, for example, used sparkles to represent population.
The final models are nice for trying stop-motion fly-throughs.
In the early stages of the formation of a solar system, dust in the nebula around a young star is attracted to each other because of their minute gravitational attraction to each other.
In the video below, accumulation of dust and gas creates a planet, probably a gas giant, that clears a swath of the solar nebula.
“My life would be worthless without music.”
— Young Paraguayan violinist.
The Fulton School has a wonderful music program, so I’m hoping that this video, about how Paraguayan children living in a slum on a landfill have recycled classical instruments out of the trash, resonates with some of my environmental science students.
Landfill Harmonic film teaser from Landfill Harmonic on Vimeo.
Of course, we’ve seen other instruments invented out of discarded trash. The BBC has a brief history of the steel pan, but Trinbagopan.com has an much more detail. On the other hand, I prefer my history in a musical form.
Zoe Rodriguez del Rey tried to measure the caffeine concentration in the seawater off Oregon by measuring its concentration in mussels. It’s an interesting measure of just how the stuff we eat and drink can affect the environment. Curiously, del Rey and her colleagues found lower concentrations near the cities’ sewage treatment plants compared to areas further away from the cities.
Scientists sampled both “potentially polluted” sites—near sewage-treatment plants, larger communities, and river mouths—and more remote waters, for example near a state park.
Surprisingly, caffeine levels off the potentially polluted areas were below the detectable limit, about 9 nanograms per liter. The wilder coastlines were comparatively highly caffeinated, at about 45 nanograms per liter.
“Our hypothesis from these results is that the bigger source of contamination here is probably on-site waste disposal systems like septic systems,” said study co-author Elise Granek.
— Handwerk (2012): Caffeinated Seas Found off U.S. Pacific Northwest in National Geographic.
Rick Nevin‘s research provides a lot of evidence that the amount of violent crime — murders, aggravated assault, etc. — are the result of lead pollution. Lead was added to gasoline until the 1970’s. When the gasoline was burned in car engines, the lead was released into the atmosphere where it could get into people’s systems just by breathing.
Quite a number of studies taken together have shown that high blood lead levels result in lower IQ’s, which, in turn, seems to increase aggressive behavior.
Long-term trends in paint and gasoline lead exposure are also strongly associated with subsequent trends in murder rates going back to 1900. The findings on violent crime and unwed pregnancy are consistent with published data describing the relationship between IQ and social behavior. The findings with respect to violent crime are also consistent with studies indicating that children with higher bone lead tend to display more aggressive and delinquent behavior.
— Nevin (2000): How Lead Exposure Relates to Temporal Changes in IQ, Violent Crime, and Unwed Pregnancy (pdf pre-print) in Environmental Research.
Kevin Drum summarizes the research and goes into the details to disprove the other theories for peaks in crime rates in the last century.