The Auroras are a great natural phenomena that relates to elements, the structure of atoms, and ionization. They also tie into the physics of charged particles in magnetic fields. The video below provides and excellent overview and also brings up nuclear fusion and convection.
This video explains how particles originating from deep inside the core of the sun creates northern lights, also called aurora borealis, on our planet.
See an extended multimedia version of this video at forskning.no (only in Norwegian):
http://www.forskning.no/artikler/2011/april/285324
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This video is produced by forskning.no in collaboration with the Department of Physics at the University of Oslo.
Production, animation and music: Per Byhring
Script: Arnfinn Christensen
Scientific advisors: Jøran Moen, Hanne Sigrun Byhring and Pål Brekke
Video of the northern lights: arcticlightphoto.no
Video of coronal mass ejection: NASA
This video from NASA (via physorg.com) includes a nice little section showing the movement of charged particles (cosmic rays) through the Sun’s magnetic field. What’s really neat, is that the Voyager spacecraft (now 33 years old) have discovered magnetic bubbles at the edge of the solar system that make the particles dance a little. It’s a wonderful application of the basic principles of electricity and magnetism.
The BBC has an excellent article on the Alpha Magnetic Spectrometer (AMS) launched on the second to last shuttle flight to investigate the origins of the universe. NASA’s page is giving regular updates.
What’s nice is that the basic physics of magnetic spectrometers, where magnets are used to deflect the motion of charged particles, should be accessible to middle school students once they get into electricity and magnetism.
Transition Radiation Detector determines highest-energy particle velocities Silicon Trackers follow particle paths; how they bend reveals their charge Permanent Magnet is core component of AMS and makes particles curve Time-of-flight Counters determine lowest-energy particle velocities Star Trackers scan star fields to establish AMS’s orientation in space Cerenkov Detector makes accurate velocity measurements of fast particles Electromagnetic Calorimeter measures energy of impacting particles Anti-coincidence Counter filters signal from unwanted side particles
Comet colliding with the Sun coincides with a coronal mass ejection. Image from the NASA SOHO Observatory.
SOHO scientists think that coronal mass ejection that happens right after the comet hits the Sun was probably not caused by the collision. But it looks really cool.
Expanding globe of debris from the explosion of Tycho's Star. Tycho Brahe observed the star as it went supernova about 540 years ago. The red is the debris, the stardust, created by the explosion. Image from NASA.
We could have been talking about the nuclear meltdowns in Japan, but I’m not sure. Our conversations tend to wander. I remember trying to explain where the carbon atoms, that are so essential for life, came from. It’s been a while since we saw this topic, so I figured it wouldn’t hurt to go it over again. And then I found this wonderful image of the Tycho supernova from the Chandra space telescope. Supernovas are where the heaviest atoms are formed.
In the beginning … the big bang created just the smallest elements, hydrogen and helium. But even these tiny things have gravity, so they pull each other together until there’s so much stuff that the pressure at the center of the clump is enough to fuse hydrogen atoms together.
Now fusion is easy to confuse with chemical bonding that occurs around us every day. After all, the hydrogen in the atmosphere is usually in the form of H2, which is two hydrogen atoms bonding together by shared electrons.
With fusion, on the other hand, the single protons that make up the nuclei of the hydrogen atoms are pushed together to create a bigger atom, helium. I say pushed together, because it takes a lot of pressure to fuse atomic nuclei. And it also releases a lot of energy. Notice all that heat and radiation that comes from the Sun? All that energy was created by the fusion of hydrogen atoms; the smallest element, hydrogen, fuels the stars.
Fusion of two hydrogen atoms to create helium, compared the chemical bonding of hydrogen atoms to produce hydrogen gas (H2). The nutrons are left out for clarity.
The huge amounts of energy released by fusion makes fusion power one of the holy grails of nuclear energy research. If we were able to create and control self-sustaining fusion reactions, just like what happens in the Sun, we would have a source of tremendous energy. There is a lot of research in this area. Some people have figured out how to build fusion reactors in their basements, but these use a lot more energy than they produce so they’re not very useful as a power plant (Barth, 2010). The ITER reactor, currently being built in France, aims to be the first to produce more electricity than it uses.
Now back to the stars. Hydrogen atoms fuse to form helium, but it takes a lot more pressure to create larger atoms: carbon has six protons, nitrogen seven, and oxygen eight. These elements are essential for life (as we know it). The only time stellar forces are great enough to produce these are when stars explode; an exploding star is said to have gone nova. Bigger atoms, like iron (26 protons), gold (79 protons), and uranium (92 protons) need even greater forces, forces that only occur when the largest stars go supernova.
DNA. (from Wikipedia)
So if these elements are only produced in novae and supernovae, how did they get to Earth? How did they get into your DNA?
Well when stars explode, a lot of these newly formed elements are blasted off into space. It’s a sort of cosmic dust. We could even call it stardust. It’s matter, just like the hydrogen and helium from the big bang, only bigger, which means they have more mass, which means they have more gravity.
Formation of the solar system (model).
The gravity pulls the stardust together with the hydrogen and helium sill floating around in space (there’s a lot of it), to form new stars, and, now that there are the larger elements to create them, rocks, asteroids, and planets.
So, if you think about it, some stars needed to have been formed, lived their lives (which consists of fusing hydrogen atoms until they run out), and exploded to create the matter that makes up the planets in our solar system and the calcium in our bones, the sodium in our blood, and the carbon in our DNA.
Notes:
1. Lots of information about Tycho’s Star on SolStation.com.
I’ve been thinking about science fiction, like Mirable and The Chrysalids that tie into the Natural World (science) curriculum. While I’ve not read Kim Stanley Robinson’s Mars triology, Red Mars, Blue Mars and Green Mars, they’ve won a number of awards and I’ve heard good things about them.
I’m looking for books that address global ecology, so stories about terraforming Mars would seem to fit. The Mars triology books are also supposed to be fairly rigorous and consistent about the science, something I look for in good science fiction. There are also some good articles discussing the science that can be used for supporting information, like this one by Margarita Miranova (2008) about the actual feasibility of terraforming Mars.
Feature identified by students from Evergreen Middle School. Image from NASA.
Given Mars’ proximity and the fact that space agencies have orbiting satellites and ground rovers makes the idea of colonizing Mars an intriguing one for the more adventurous adolescents. In fact, the recent news that 7th graders discovered a new feature on Mars’ surface might also inspire some interest. The 7th graders’ project was part of the Mars Student Imaging Program (MSIP), which might also be of interest. MSIP actually allows students to use the camera on board the Mars Odyssey satellite, by identifying locations for detailed images.
This year the theme is life. My central organizing structure is the timeline of life on Earth. I plan to link all of the discussions of taxonomy, phylogeny and genetics to this timeline over the course of the year.
The timeline above will be the first lesson. As with these things the trick is deciding how much detail to keep in and how much to keep out.
What I like is that it gives the general overview of when important things happen while leaving a lot of space for students to investigate. Most of what we’ll be seeing this year happened in the Cambrian and this timeline conveys that this is a very small part of the whole history of life. In fact, it’s only when we cover the biochemistry of genetics that we will be talking about the origins of life.
The Earth's magnetic field protects us from the solar wind. Image from NASA.
Having a magnetic field protects the Earth from the charged particles spewing out of the Sun, the solar wind. This makes life on land a lot easier since the solar wind’s particles are quite damaging to DNA. However, prior to the magnetic field forming all this damage to DNA may have also accelerated mutation and thus evolution.
