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Meteorite or MeteorWrong
WhatŹ¼s this activity about?
Learn all about meteorites with this hands-on activity: where they come from, how they got here, and what they are made of. Compare the characteristics of meteorites and Earth rocks. Big Questions:
- What are the physical characteristics of meteorites?
- How can they be distinguished among a group of Earth rocks? Big Activities: Use various tests to pick meteorites from among a group of Earth rocks. Participants: From the club : One presenter Visitors: Appropriate for families, the general public, and school groups in grade 5 and up. Up to 5 visitors at a time may comfortably participate. Duration: About 15 minutes. Additional time can be used for discussion and extensions. Topics Covered:
- Where meteorites originate and how they end up on Earth
- Types of meteorites and what they are made of
- Characteristics of meteorites
Where could I use this activity?
What do I need to do before I use this activity?
What materials from the ToolKit are needed for this activity? What do I need to supply to run this activity that is not included in the kit? Preparation and Set Up
- Set of rocks and meteorites
- Flipbook
- Magnet
- Magnifying Glass
- Bag that is used for sorting It is helpful to have a table or flat surface to spread the rocks on. - Remove the sliced meteorite (with no dot) from the set of rocks. - Place the rest on a flat surface or on the bag for your visitors to see. - Keep the sliced specimen and the magnet out of view until needed. - Begin the flipbook with the title page facing your audience and the words "Start Here" facing the presenter (page 1). ACTIVITY Star Classroom Party Pre-Star Party ā Outdoors Pre-Star Party ā Indoors Girl Scouts / Youth Group Meeting K- 4 5 - 8 9 - 12 Club Mtg Gen Public Presentation (Seated) Gen Public Presentation (Interactive) Meteorite/MeteorWrong ā ā ā ā ā ā ā
to be extremely oxidized are further treated to remove rust and hopefully prevent future oxidation.
- The meteorite samples are next baked in an oven to dry and further dehydrate the samples. One does not want too high a temperature; around 175 o F is about right. The baking process takes between 30 and 60 minutes depending on the size of the meteorite(s).
- Finally, each sample is lightly coated with a spray that was specifically formulated for meteorites.
- There is no need to treat tektites in this manner since they are dry, glassy materials. However, each tektite was cleaned and rinsed in EtOH.
Key to Meteorite or MeteorWrong Rocks
- Pumice - porous volcanic rock
- Stony meteorite (same as unmarked slice) - Northwest Africa 869 Ordinary Chondrite (L5); brecciated, NWA869 was discovered in 1999. It is estimated that 1,500 kg have been recovered, making NWA869 one of the largest total known weight meteorites to come out of Northwest Africa. When cut and polished, the matrix is full of color and chondrules.
- Lodestone - a naturally magnetized piece of the mineral magnetite. They are naturally occurring magnets that attract pieces of iron. They are often mistaken for meteorites.
- Iron meteorite - Sikhote-Alin Found in Russia. Coarsest Octahedrite (IIAB) This wellāobserved fall occurred on February 12, 1947 over the Maritime Territory. A shower of fireballs fell in the thick-forested SikhoteāAlin Mountains. According to eyewitnesses, the fireballŹ¼s brightness exceeded that of the Sun. The SikhoteāAlin fall produced 106 impact holes and over 27, kilograms of meteorites.
- Fossil ā This is a piece of a turtle shell that has been fossilized in the creeks of Florida. They are called "Turtle Skutes" and naturally fall off of turtles as they grow. On most fossils, you can see where the piece of shell was once fused to the vertebrae. They are between 10,000 and 4 million years old.
- Tektite - Chinese Tektite Found in the Australasian Strewn Field, Composition-wise, tektites are extremely dry fused glassesāthat is, they contain very little water. They are silica-rich (SiO 2 ) with a form that indicates aerodynamic flight, including spheres, ellipsoids and spheroids, dumbbells, and teardrops, with spheres being the most-common form.
- Pyrite ā a naturally occurring Earth mineral. It is an iron sulfide with the formula FeS 2. It is also called "fool's gold" because of its appearance.
- Marble ā a metamorphic rock (made from calcite or dolomite) commonly used in sculpture and building materials.
Detailed Activity Description
Meteorite or MeteorWrong
Presentation Tips: The flipbook is a useful tool to use with this activity. It gives the audience visual reinforcement of the concepts. And it doubles as a reminder of points to cover in the activity for the presenter. In the "Activity Description" below, the column on the left indicates when to turn to the next page in the flipbook and what image the visitors will be seeing. (Only the presenter pages are numbered.) Included in the black bag is a key to the rocks and meteorites. To help you remember what you are looking for, the meteorites and tektite are labeled 2, 4, and
The rocks and meteorites are numbered to ensure you pick the correct meteorites. You will also find the key to the numbers on page 13 of the flipbook. Page LeaderŹ¼s Role ParticipantsŹ¼ Role (Anticipated) 1 Intro/ Start Here To say: Hey, I have some cool rocks from outer space here. Can you figure out which of these rocks are meteorites? It's impossible to tell just by looking. Would you like to become a meteorite detective and see if you can find one? Are you ready for some clues? Our first clue comes from how they got here. Between outer space and the ground here on Earth, what do they have to travel through? Yes! Yeah Atmosphere
Page LeaderŹ¼s Role ParticipantsŹ¼ Role (Anticipated) Misconception Tips: Many people think that meteorites are hot when they land on the Earth. For small meteorites, that is not the case. Only the very outer layer of the rock has time to heat up. Most of the mass of a meteorite is lost as the outside layer vaporizes in the atmosphere, leaving only a thin fusion crust by the time it hits the ground. Heating of the surface of the rock (the meteor phase) only lasts a few seconds upon entering the atmosphere and normally stops between 15 to 20 km (9-12 miles) altitudes. After this point, they are moving at only about 0.2 km/sec and there is minimal heating from friction. They are free falling through the atmosphere for a minute or two and it is very cold that far up. So meteorites are most likely to arrive on the ground about room temperature. Imagine holding a piece of metal over a flame for a few seconds then putting it in the freezer for a minute. The interior never heats up and the heat on the top layer dissipates quickly. Contrary to what most people have learned, the glow of meteors is not caused by friction. The great speed of a meteoroid entering the atmosphere (average 30 km/sec or 20 miles/sec) compresses the air in front of it, causing the outer layer of the rock to heat so that it glows and vaporizes. 5 Asteroid Belt To say: Okay, so now we're down to strong, dark rocks without holes. We'll get the next clue when we figure out where space rocks come from. Does anyone know where meteorites come from originally? Right. More specifically, almost all meteorites found on Earth originally come from the Asteroid Belt. They are pieces of an asteroid. Way out past the orbit of Mars, asteroids collided and pieces of them were scattered. Just a few end up here on Earth as meteorites. So when you hold a meteorite, you're actually holding a piece of an asteroid. Space.
Page LeaderŹ¼s Role ParticipantsŹ¼ Role (Anticipated) 6 Planets Asteroids To say: All of the rocky planets and asteroids formed from the same space stuff- mostly dust, rock, and metal. But here's the thing that makes asteroids different from planets like Earth. Most never got very big. And this gives us a clue. Let me explain. When Earth and the other rocky planets formed from space dust, they got big enough and hot enough that most of the metal liquefied and sank to the core. Does anyone know what the Earth's core is made of? Right, well, most asteroids never got very big so all of these little bits of material are still stuck together just the way they arrived. And the metal never heated up or sank to the core. So in most asteroids, there's metal all mixed in with the rock. Meteorites from these asteroids are called stony meteorites. Now, there are some exceptions. Some asteroids did get big enough to have a core. And these also get smashed apart sometimes. When they do, the bits of metal from the core can land on Earth too. We call these iron meteorites. Iron Tip: An astute audience member may ask why we don't see many meteorites from the crust/mantle part of these large asteroids. This question is as yet unanswered by scientists as well. 7 Scale To say: But either way , it turns out that 99% of meteorites found on Earth have a good amount of iron in them. And iron is heavy. That makes a meteorite heavier than an average Earth rock of the same size. Go ahead; pick up some of the rocks. If any of them weigh considerably less than another of the same size, it's probably not a meteorite. Make sure to compare rocks of about the same size for this test.
Page LeaderŹ¼s Role ParticipantsŹ¼ Role (Anticipated) See Background Information for more details on slag and lodestone. 9 Iron Meteorite 10 Chondrules 11 Tektites To say: Now this is an iron meteorite! The largest meteorites on Earth are iron meteorites. Can you guess why? They are really strong and more often make it to the ground in one piece. To do: Pick up iron meteorite (#4) and pass to a visitor. To say: Only the most careful meteorite detectives pick out this one. This is the stony meteorite (#2). To do: Also pick up the stony if you they haven't already picked it out. Now bring out the sliced chondrite to show the interior- the chondrules and metal flakes To say: Here you go. I have a stony meteorite that has been sliced open. With that magnifying glass, you can easily see the metal flakes and pieces of rock or chondrules. (Pronounced: con - drools) Congratulations! You are now holding pieces of the Asteroid Belt. These also happen to be older than any Earth rock. They are glimpses into what our Solar System looked like when it was first forming. Now there's one other thing in here that's not a meteorite but that is related to Earth impacts. To do: Pick up the tektite (#6) and point out features before passing it around. They are bigger to start with?
Page LeaderŹ¼s Role ParticipantsŹ¼ Role (Anticipated) 12 Other Kinds 13 Looking for Meteorites To say: When very large asteroids or comets impact the Earth, they explode with so much energy that they heat up the rock or sand they hit and can leave a big crater. The energy from that impact heats the rock and sand up to such high temperatures that they can melt. (For older visitors) Does anyone know what happens when sand gets super-heated? That's right, melted sand becomes a kind of glass. This is a piece of glass that splashed out of an impact site. It's called a tektite! There are also types of rare meteorites, from the Moon, Mars, and very specific parts of an asteroids, like the boundary between the core and the mantle. It's hard to come up with characteristics that fit every meteorite, but the tests we just did will help identify over 90% of meteorites out there. Does anyone want to see if you can pick out the two meteorites in this picture? It's still not easy. Here are some tips if you want to be a meteorite hunter:
- Look in a place without lots of other rocks to fool you. What kind of place might that be? o Right, or even a freshly plowed field.
- Get a good book about meteorite hunting from the library or a bookstore. Good luck! Older students and adults may know it becomes glass. Sure! (Try it) Desert?
