Green Folly

On Friday I had the opportunity to teach a unit on meteorites to a 6th grade science class.  The class was wrapping up a unit on Earth and Space and through my daughter, the teacher was very interested in me bringing in meteorite samples to show the class.  I had no idea what to expect so I created a simple set of definitions and fun facts (listed below) and I chose some representative specimens from the stony, iron, and stony-iron groups:  a 350g SAU 001 end cut that is also shows a great fusion crust example, an etched Campo del Cielo slice as an example for a Widmanstatten pattern, and a very large Pallasovka pallasite slice as an example of a stony-iron.  In addition, as the proud owner of the facecitiously named “World’s ugliest Halloween Meteorite” lot, I also brought in a set of NWA Unclassified specimens from this lot in order to hand out to the kids.

The session lasted for 40 minutes and started pretty slow.  I started going down the one-sheeter I brought while also circulating the SAU 001 and Campo items to the kids for them to feel and look at.  Most could not believe that it had come from outer space.  A few sniffed the meteorites (which I never thought to do!) and said they smelled metallic/coppery.   As they looked at the fusion crust on the SAU 001, I was able to get them to understand that the amount of friction/heat involved when a meteoroid enters our atmosphere is large enough to start melting the specimen.

Once I brought out the large Pallasovka, questions started flying.  The children were engaged and started asking some great questions:

1. How do people find meteorites?
   1. I explained how many meteorites are found in desert like conditions due to the distinct color differences between the meteorite and the surrounding area
2. How big of an impact crater would each sample make?
   1. While I could not give exact numbers, I was able to explain that a meteorite would make an impacat crater that is bigger than the meteorite itself.
3. Why is it called a Widmanstatten pattern?
   1. This was a good time to explain a perk of scientific discovery.  If you are first, you have a good shot to have the discovery named after you.
4. How does the meteor move through the atmosphere?
   1. This was an interesting one.  I did not understand this one at first ut he was interested in how the fusion crust formed uniformly.  I explained how it most likely rotates while falling, allowing the fusion crust to be somewhat uniform.  This was an off the cuff answer but seemed to suffice.
5. Are we able to track meteorites before they hit us?
   1. Even though this just happened, I said that they are able to do this for asteroids but that they can’t do it as well for meteorites yet due to the size differences.  In addition, I was able to explain the concept of distance from an astronomical point of view.  Specifically, if someone says that an asteroid is “close”, it is not the same as “my house is close to the school”.  It is more like “Mars is close to Earth”.
6. The ambitious boys asked if the NWA Unclassified meteorites could be sold on eBay.
   1.  I told them that it is possible but their best bet was to get it classified.  After raised their hopes, I let them down by telling them that classification costs money – more than a 11 year old would have most likely.

Overall, I had a great time and hope I can do it again.  Here is the one sheeter I used to guide my discussion:

Some Definitions

meteoroid, meteor, meteorite: A small rock in space is called a meteoroid. As the meteoroid passes through our atmosphere and generates light, it is called a meteor (or a shooting star). Once the meteor hits the ground, it is called a meteorite.

Fusion Crust: When a meteoroid is entering our atmosphere at high rates of speed, it compresses the air in front of it, generating massive amounts of heat and light. As a result, the meteor starts to melt. Once the melting stops and the meteor starts to cool down, a thin glossy coating forms on the meteor. This is the fusion crust

Widmanstätten Pattern: patterns formed by iron – nickel crystals as they cooled over many years in space. Once a meteorite is etched with acid, you can see the pattern.

Oxidation: when a meteorite with iron in it is exposed to oxygen (like in our atmosphere), the iron will turn to rust due to the process of oxidation

Impact Crater: A depression formed by the high velocity impact of a smaller body into a larger one (think of the craters on the moon – they came from meteoroids!)

Some facts

1. Meteorites contain the oldest known rocks in our solar system.
2. The Chesapeake Bay was formed by an impact from an object from space (perhaps a meteorite or comet) over 35 million years ago. The Bay is an impact crater. It is the largest impact crater in the United States!
3. Meteorites are named for the locale, region, or nearby town in which the “fall” occurred (like Campo del Cielo, Argentina or Pallasovka, Russia).