A Geologist Explains to Webelos why Rocks and Minerals are Important
A Talk to Webelos from Mikey the Geologist
Who is a geologist? A geologist is someone who studies the past history of the earth and its life by studying rocks, minerals, and fossils. Just as you read a book to understand a story, a geologist reads rocks. He is taught in college to carefully examine any sample or outcrop of rock or mineral and make note of many features, such as:
What it is made of.
Its form and shape.
How it has weathered.
If present as fossils, the types of plants or animal life recorded in the rock.
Geologists have been gathering historical information concerning rocks and minerals for over 300 years, and they have been doing these activities all over the world. Many geologists travel to remote places around the world, looking for information no one else has discovered. Since geologists study the earth and its processes, they get to check out a lot of really interesting things, including volcanoes, islands, mountains, rivers, beaches, rocks containing dinosaur bones or diamonds or oil, and the form or shape of the earth's lands and oceans.
Knowing about our planet is important
There are two important reasons for doing such activities. First, the more we know about the earth and how it formed and came to be as it now is, the better we know how to take care of our planet and its environment. Second, many products and things we take for granted come from the earth. The more we know about them, the wiser we can be in our use of them. See page 177 of the Scout book.
The saying: "If you can't grow it, you have to mine it" comes to mind. We now live in a very different world than people did just a 100 years ago. Most of what we have gained in that time has been the result of man's increasing knowledge of how to use materials around us. Whatever we use that comes from the earth, we want to use it wisely, and with great care, because the earth contains only so much as far as minerals and fossil fuels are concerned. They do not grow back in our lifetime, like trees, crops, or animals. Geologists call these kinds of natural resources non-renewable. If we are careless and waste these resources, then when you grow up and have children, they may not have the resources to have a life that is as enjoyable as ours. This could happen simply because they would not have the materials to make what they need.
So let's look at some of the things geologists know or do that are activities that will help you get your badge!
A big dump truck of rocks and minerals
I could talk my entire time about how people use rocks and minerals, but I think that a couple of examples will give you some important information. But first you should know how much each person in the United States uses every year – 20 tons ( a BIG dump truck full). That's a lot of rocks!!
What are they? If your yearly quantity of rocks, minerals, and metals arrived as a single delivery, it would consist of mostly crushed stone and sand and gravel, 10 sacks of cement, almost equal amounts of clay and salt, some phosphate rock, and over 1,000 pounds of other nonmetals, along with well over 1,000 pounds of metals and 9 tons of fuel, like petroleum, coal, natural gas and uranium! Note that a portion of these materials are divided into those things composed of metals and those that are not. We call them metals and nonmetals. A big dump truck load of these metals and industrial minerals would be delivered to every person in the country every year.
How do we use these rocks?
The nonmetals stone, sand and gravel, and cement make up more than 80 percent of the total and are used mostly to make concrete for the construction of highways, driveways, sidewalks, dams, many buildings, and the foundations of most homes and offices. Next is clay, which has a variety of products, including bricks, many types of ceramic tile, porcelain fixtures, and even coating on this paper. Most salt is used to remove ice from roadways and to make many chemicals. Phosphate rock, through processing, becomes fertilizer and a part of many detergents. In the other nonmetals, we find many rocks and minerals with special or unique properties that make them invaluable. Last are the metals, which make up less than 10 percent of our total yearly usage, but are absolutely indispensable because of their large variety of uses.
Two examples of the use of rocks and minerals:
A major use of concrete is in the construction of highways. Take Interstate 40, a four-lane highway extending 284 miles across Arkansas from the Mississippi River on the east to Oklahoma on the west.. Its construction required approximately 4,500,000 tons of concrete (composed of crushed stone and cement), 300,000 tons of steel as reinforcement and guard railing, and another 3,200,000 tons of crushed stone and 40,000 tons of asphalt (a product of oil) for the shoulders. To simplify the calculations, we ignored bridges and access and exit ramps. These big numbers mean that's a lot of rocks and metal!
Among the metals, steel is the most widely used. The automobile industry is a major consumer. About 5,500,000 automobiles are built each year in the United States. An average car contains over 2,000 pounds of steel, 160 pounds of aluminum, 70 pounds of copper, zinc, manganese and other metals, and more than 200 pounds of plastics, made from oil and natural gas. The car's fuel, lubricants, and antifreeze are also made from oil, as are the automobile's paints, tires, and most upholstery. Did you ever think of a car coming from out of the earth? Well, all its raw materials do.
Rock and Mineral Collections
To help you see some examples of different geologic specimens that have important uses, check with your state geological agency.
Hardness Scale for Minerals
Rocks are made up of minerals. Minerals have certain physical properties which allow us to identify one from the other. One of these properties is hardness. Hardness is nothing more than a measurement of if one mineral can scratch another one. A long time ago a man named Moh took a lot of minerals and tried scratching them with each other. He found that they varied in hardness from very soft to very hard. He made a scale we still use today called the Moh's Hardness Scale. On his scale, the number 1 is the softest and the number 10 is the hardest mineral. His hardness scale is given on page 186 of your Webelos book. Each mineral will scratch those which are softer and be scratched by those that are harder. Every mineral will scratch talc (hardness of 1) and only one mineral, diamond, can scratch every other mineral.
Here's the jingle to remember the Moh's Scale of Hardness:
The girl could flirt and flirt quickly though Connie didn't.
Talc Gypsum Calcite Fluorite Apatite Feldspar Quartz Topaz Corundum Diamond
There are some common things around which you can use to make your own hardness scale. A fingernail is 2.5 on Moh's scale, a solid copper penny is 3, an iron nail is about 5.5, window glass is about 6 and pop bottle glass around 6.5. A piece of quartz, which is a very common mineral and is in your rock set, is 7. Quartz is the hardest of all the common minerals. To use this homemade hardness scale, you must try to scratch each of the items with your unknown mineral. To know if a real scratch was made, you must be able to see the scratch and feel with the edge of your fingernail that a groove was cut in the item you tried to scratch. If the mineral is softer than the item in your hardness scale, it will not leave a scratch, but might leave a trail of powder behind. So you must feel to see if there is a real scratch made. The unknown mineral is harder than anything it scratches and softer than what it will not scratch. Let's look at an example. Let's say we have tried to scratch all our hardness set with an unknown sample and here are the results:
Sample scratches fingernail, is not scratched by fingernail.
Sample scratches pocket knife blade, is not scratched by knife blade.
Sample does not scratch quartz, but is scratched by quartz.
So, using the homemade hardness scale, we have discovered that the unknown mineral is between 5.5 and 7 in hardness. There are tables in mineral books that you can look at that tell you the minerals within this hardness range. Only a few of the many known minerals have a hardness that fall into this range. The entire purpose of this exercise is to recognize that an easily recognized property, like hardness, is an important key to learning how to identify a mineral. Many other properties, like color, luster, crystal system, cleavage, common habit, and so forth are used by geologists to help when they look at a mineral sample. The average geologist is familiar with around 100 common minerals, whereas a mineralogist (a geologist who specializes in mineral study) may be recognize 500 to a 1000 different minerals! He is a scientist who really likes to study minerals. This brings up an interesting question.
What are minerals? They are simply nature's natural chemical compounds. There are now over 4000 known minerals described by mineralogists. Each has different properties and chemical composition from the others. Rock collectors, often called rockhounds, are people who enjoy collecting and learning about rocks and minerals as a hobby.
Geologic materials in your home
Now let's think for a minute about what you house is made of. Do you live in a mobile home, brick house, wood frame house, or an apartment house? All of these have some things in common. And some things that are different. We will talk about what they have in common.
The framing in all of these buildings is usually wood, held together with steel or iron nails. The inside walls are often composed of wallboard, which is made from the mineral gypsum. Electricity, often made by burning petroleum, coal, or natural gas, is available by plugging into the wall outlet. Electricity flows along copper or sometimes aluminum wiring that's inside the walls. The pipes that bring water into and remove it from the house are often made of copper or cast iron, though some may be plastic (made from oil). Does your house have a toilet? Do you eat off of china plates? These items are made from clay. Do you have windows in your house and do you drink from a glass? These items are made of glass, which is made from quartz sand and limestone. Do you have light fixtures, light bulbs in those fixtures, a refrigerator, a washing machine, and/or a dryer. These items contain glass, metal, and other mineral materials. Below is a list of some minerals and their metal or nonmetal product that is probably in your house.
| Mineral/Rock | Metal/Nonmetal | Product |
| Azurite, malachite | Copper | Wire |
| Scheelite | Tungsten | Light-bulb filament |
| Quartz sand | Silica | Glass |
| Hematite | Iron | Steel, nails, many machines |
| Clay | Clay | Brick, china, porcelain |
| Bauxite | Aluminum | Metal trim, aluminum foil |
| Argentite | Silver | Jewelry, mirror coating, old coins |
| Gold | Gold | Jewelry, computer, dental work |
| Cinnabar | Mercury | Thermometer, tooth filling |
| Gypsum | Gypsum | Wallboard, plaster |
| Syenite | Aggregate | Concrete, shingle coating |
| Limestone (calcite) | Lime | Concrete binder |
| Sand and gravel | Aggregate | Concrete |
| Diamond | Diamond | Phonograph needle, jewelry |
| Chromite | Chrome | Toaster wire and metal plating |
| Rutile | Titanium | Pigment in white paint |
As you can see, there are many. And this is only a partial list. Maybe you can come up with more!! See the list on page 181 of your Webelos Scout book for help.
Mountain Building Processes
We are going to discuss one type of mountain and how they form – the volcano. Volcanoes are simply a place where there is an outlet for molten rock, called magma, to reach the surface of the ground. When the magma pours out, it is called lava. Geologists love to look at and study volcanoes. They are one of several types of mountains. Volcanoes come in a variety of sizes and types. One type is like those of the Hawaiian Islands. They rise from the floor of the sea and emerge from the ocean to form the islands. If they were not in the ocean, these volcanoes would make some of the tallest mountains in the world! It takes millions of years of lava flows to build up a volcanic mountain by flow after flow cooling and becoming solid rock. Each layer hardens into rock and helps build the mountain. This type of volcano is called a shield volcano.
Some types of volcanoes are built by eruptions of ash and cinders. They are very steep sided and form a shape that everyone recognizes as a volcano. They often have blocky lava associated with them. This type is called a cinder-cone volcano. An extinct cinder cone volcano may be visited in northeast New Mexico and is called Capulin. See page 190 in your scout book to see a map of how to get to this volcano.
Another type of volcano, termed a composite, is a combination of both the shield and the cinder-cone types. They are present in the United States in Alaska, Washington State, Oregon, and northern California. Mount St. Helens, Mount Rainier, and Mount Hood are all composite volcanoes. This type of volcano, the composite, is one of the most dangerous types of mountains known to man. They may sit quietly for hundreds of years and then explode, almost without warning, due to the slow buildup of gas. Crater Lake in Oregon is a beautiful freshwater lake in the middle of the exploded crater of an extinct volcanic mountain that was called Mount Mazama.
Many things about living near a volcano may be dangerous, aside from the possibility of lava burning down your house or the volcano blowing up and covering you with hot ash. A hot gas cloud sometimes comes out of the volcano at 200 miles an hour! You can't outrun that even if you could get on the freeway and drive as fast as your car can go. Sometimes a gas, like carbon dioxide (which is heavier than air), may come out from under a lake in a crater and flow along the ground in a cloud, suffocating entire towns – people and animals. This happened a few years ago in a country in Africa. Also, as lava moves around in the ground, back and forth and up and down, it causes lots of earthquakes. Usually they are small and don't cause too much trouble, but sometimes they are strong enough to cause major problems. I don't think that I'd want to live on the side of a volcanic mountain, how about you? See pages 187 to 191 of your Scout book for more information about volcanoes. Check on Google for links to video of live volcanoes.
The Boy Scout merit badge is quite involved. See the next link for its requirements.
To learn more about the hobby of rock and mineral collecting, you'll find an enormous amount of information here at Rockhounding Arkansas.
Yours in scouting,
Darcy
former Webelos Leader, but always an Eagle Scout mom
Have pictures to share of your scout activities involving earth science? Send s0me to us!