Bring it to the Classroom !
Students need to be ENCOURAGED to ask questions! Students need to KNOW they are smart enough to look for answers! Students need to be taught how to REASON using the scientific method! Students need their IMAGINATIONS ignited! Students need to know it’s ok to CHALLENGE ideas and theories!
Most kids love fossils! I have found that one good way to put this all together is to use the creation of fossils to bring the scientific method to life.
How to create your own fossils:
The fixture shown below was created from scrap and readily available parts. The piston and cylinder are 3 inches in diameter. The small holes drilled in the ends are for water to pass as the clay is slowly pressed. I was surprised to find out that normal natural clay taken right out of the ground and used by potters is about 20 -25% water by volume and works very well. I am told by geologists that this is a very good medium since about 70 to 80% of the fossil record is found in some form of mudstone formed from silt and clay. A local potter runs my clay through a Pugmill and it comes out in a long cylinder of just the right diameter. Using a string wrapped around the clay, you can cut approximately 1/2 inch thick discs that will fit right into the main cylinder. Five, 1/2inch discs will fit into the cylinder giving you 4 layers of fossils. After stacking all five layers, gently wrap them in a paper towel to hold them together. You will first place a coarse stainless steel screen on the bottom of the cylinder then a fine screen and a cotton filter (old denim works well). The cotton filter prevents the clay from extruding through the screen and holes allowing only pure water to be pressed out. The clay discs are then inserted, followed by a filter, fine and coarse screen. The bolts are then inserted from the bottom and the piston placed on top. Five or six spring washers known as Belleville washers are stacked in series on each bolt followed by a nut. By using Belleville washers of a known strength I can determine how much force is being placed on the sample. In this case, the washers flatten at approximately 2600 lbf, times 8 bolts gives about 21,000 lbf, divided by 7 square inches, gives us about 3000 psi. The whole fixture is then placed into a common kitchen style oven at 450 to 500 degrees F. Compressing the clay sample slowly will take about 4 to 5 hours and then it will be in the oven for another 12 to 24 hours. After cooling, unscrew the cylinder with the sample. The sample will then have to be pressed out using a hydraulic or arbor press. To break the sample apart I use a sharp knife to score the mudstone cylinder around each of the five layers, and then tap the blade with a small hammer as I roll the cylinder.
You will notice as you study the above results that the old dried leaves still look old and crispy, and the fresh leaves still look fresh. Even the ferns that were turning brown at the ends look the same. The feathers and leaves, although turned to carbon leave a very detailed impression. The finer the clay or sedimentary matrix, the finer the detail. You will observe the same in naturally formed fossils.
These types of fossils are commonly called “Mold Fossils” or “Carbonaceous Fossils” since the organism being fossilized only leaves a carbon film, imprint or “Mold” behind in the sedimentary matrix. Although you cannot tell from these pictures, the matrix although very hard, is not cemented together and will dissolve when soaked in water. Given time and the right conditions these fossils in nature, would probably be filled with crystalized minerals in a process called “permineralization” and become a “Cast Fossil”. The hard clay matrix would likely be cemented into stone like Mudstone, Siltstone, or Shale.
Please email me at Research@PaleoGenesis.org if you would like more information.
