Tell If a Rock Is a Meteorite?
The Earth receives a constant influx of burning debris from space that consist of rocks, portions of planets and remnants of asteroids. These rocks fall all over the Earth, and you can find them among the rocks from this planet. Space rocks have unique features, and you should be able to distinguish extraterrestrial rocks from homegrown ones.
Instructions
1. Examine your rock samples for the presence of a fusion crust. The thin crust looks black, but years after the meteorite has fallen to Earth, the crust begins to wear away. Check the inside of the rock if it is exposed. A bumpy, irregular feature known as a regmaglypt may appear on the surface or interior of some meteorites. Iron meteorites often have these regmaglypts all over their surface.
2. Test the density of the rock. Meteorites almost always contain metal, specifically iron. However, you could easily find non-extraterrestrial, metal-containing rocks or iron slugs on Earth. Meteorites have a unique quality because the iron also contains about 7 percent nickel. Meteorites also have a higher density than Earth rocks. You can compare two rocks of similar size. One should be the rock you suspect is a meteorite. Calculate the density of the rocks. First, weigh each rock on the balance. Record the results. Using a measuring cup or container, fill the container halfway. Make a note of how many ounces of water you put in. Now immerse the first rock. Make a note of the water level on the measuring cup. The difference between the first and second measurements is the volume. Divide the weight that you measured by volume you just calculated to get the density. Compare your results with the density of known Earth rocks. You can find this information in the library, online and in most general science books.
3. Check to see if the rock has metal by testing it with a magnet. Some fairly common Earth rocks have the minerals hematite or magnetite. Magnetite has a strong magnetic charge and hematite has a fairly weak charge. Earth rocks with hematite or magnetite may feel heavy, compared with other rocks of similar size.
4. Perform a streak test on your rocks. If you have a piece of floor tile, then you can use it for the test. Turn your tile so that the dull side faces up. Take your rocks one at a time and rub them back and forth over the surface of the tile. Make a note of the streak's color. Do the same for the other rock samples. If you see a black-gray streak, then the rock might be magnetite. If you see a reddish-brown streak, then you may have hematite. If after rubbing a rock you see no streaks, then your rock might be a meteorite.
5. Find an educational institution that has a geology department, if you want to further pursue your testing. Inquire about having your rocks tested, using a scanning electron microscope energy-dispersive specrometer. This expensive piece of equipment allows you to accurately identify the chemical composition of the rocks. If the tests show that the rocks have only iron, then they are from Earth. Extraterrestrial rocks have a mixture of iron and nickel.
Tags: rocks have, Earth rocks, Make note, your rocks, have unique, hematite magnetite
